Getting to know your data

Claus O. Wilke

2025-02-17

Any data analysis should start with basic quality control

  1. Assess data relevance
    (Can the data answer your question in principle?)
  1. Assess data provenance
    (Where does the data come from? Is it reliable?)
  1. Clean data if required
    (In practice, this is 70-80% of data analysis work)
  1. Perform descriptive analysis and sanity checks
    (Inspect summary statistics, distributions, scatter plots, etc.)

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

 

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Accuracy means low bias, precision means low noise

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Is the data documented? Is it machine-readable?

Usability requires a data dictionary

Data Dictionary
A “centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format” (Wikipedia)

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Is the data documented? Is it machine-readable?

Are entire records missing? Are observations missing?

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Is the data documented? Is it machine-readable?

Are entire records missing? Are observations missing?

Does data vary among sources or over time?

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Is the data documented? Is it machine-readable?

Are entire records missing? Are observations missing?

Does data vary among sources or over time?

Do you have access to the data? Can you obtain it?

Components of data quality

•  Accuracy

•  Precision

•  Usability

•  Completeness

•  Consistency

•  Accessibility

•  Relevance

Does the data contain any systematic errors or biases?

How affected are observations by random errors/noise?

Is the data documented? Is it machine-readable?

Are entire records missing? Are observations missing?

Does data vary among sources or over time?

Do you have access to the data? Can you obtain it?

Can you use the data to address your question?

Inspecting and cleaning a dataset in R

The dataset: Births in NC

Details and Source
This dataset contains data on a sample of 1450 birth records from 2001 that statistician John Holcomb at Cleveland State University selected from the North Carolina State Center for Health and Environmental Statistics.

The dataset has 1450 observations on 15 variables.

Variable Description
ID Patient ID code
Plural 1=single birth, 2=twins, 3=triplets
Sex Sex of the baby: 1=male 2=female
MomAge Mother’s age (in years)
Weeks Completed weeks of gestation
Marital Marital status: 1=married or 2=not married
RaceMom Mother’s race: 1=white, 2=black, 3=American Indian, 4=Chinese, 5=Japanese, 6=Hawaiian, 7=Filipino, or 8=Other Asian or Pacific Islander
HispMom Hispanic origin of mother: C=Cuban, M=Mexican, N=not Hispanic, O=Other Hispanic, P=Puerto Rico, S=Central/South America
Gained Weight gained during pregnancy (in pounds)
Smoke Smoker mom? 1=yes or 0=no
BirthWeightOz Birth weight in ounces
BirthWeightGm Birth weight in grams
Low Indicator for low birth weight: 1=2500 grams or less
Premie Indicator for premature birth: 1=36 weeks or sooner
MomRace Mother’s race: black, hispanic, other, or white

Start with a cursory inspection

NCbirths <- read_csv("https://wilkelab.org/SDS366/datasets/NCbirths.csv")

NCbirths
# A tibble: 1,450 × 15
      ID Plural   Sex MomAge Weeks Marital RaceMom HispMom Gained Smoke BirthWeightOz BirthWeightGm   Low
   <dbl>  <dbl> <dbl>  <dbl> <dbl>   <dbl>   <dbl> <chr>   <chr>  <dbl>         <dbl>         <dbl> <dbl>
 1     1      1     1     32    40       1       1 N       38         0           111         3147.     0
 2     2      1     2     32    37       1       1 N       34         0           116         3289.     0
 3     3      1     1     27    39       1       1 N       12         0           138         3912.     0
 4     4      1     1     27    39       1       1 N       15         0           136         3856.     0
 5     5      1     1     25    39       1       1 N       32         0           121         3430.     0
 6     6      1     1     28    43       1       1 N       32         0           117         3317.     0
 7     7      1     2     25    39       1       1 N       75         0           143         4054.     0
 8     8      1     2     15    42       2       1 N       25         0           113         3204.     0
 9     9      1     2     21    39       1       1 N       28         0           120         3402      0
10    10      1     2     27    40       2       1 N       37         0           124         3515.     0
# ℹ 1,440 more rows
# ℹ 2 more variables: Premie <dbl>, MomRace <chr>

Pay attention to the data types of each column

What’s going on with the Gained column?

Missing values were not read correctly

NCbirths |>
  pull(Gained)
   [1] "38"   "34"   "12"   "15"   "32"   "32"   "75"   "25"   "28"   "37"   "45"   "52"   "26"   "31"  
  [15] "40"   "51"   "45"   "25"   "0"    "20"   "20"   "38"   "15"   "3"    "9"    "37"   "30"   "40"  
  [29] "37"   "56"   "48"   "4"    "43"   "40"   "25"   "53"   "15"   "19"   "26"   "32"   "25"   "50"  
  [43] "34"   "2"    "23"   "16"   "48"   "80"   "19"   "16"   "50"   "55"   "25"   "33"   "10"   "30"  
  [57] "30"   "#N/A" "55"   "38"   "33"   "49"   "14"   "18"   "40"   "30"   "17"   "45"   "15"   "31"  
  [71] "50"   "25"   "12"   "38"   "47"   "20"   "40"   "34"   "5"    "25"   "18"   "27"   "46"   "31"  
  [85] "48"   "15"   "51"   "12"   "33"   "17"   "25"   "31"   "24"   "16"   "18"   "40"   "16"   "57"  
  [99] "18"   "29"   "45"   "18"   "11"   "20"   "50"   "26"   "20"   "35"   "12"   "38"   "50"   "28"  
 [113] "34"   "41"   "20"   "5"    "30"   "35"   "16"   "32"   "40"   "30"   "28"   "25"   "50"   "25"  
 [127] "0"    "7"    "24"   "34"   "40"   "32"   "25"   "25"   "25"   "0"    "47"   "45"   "34"   "46"  
 [141] "40"   "38"   "0"    "35"   "10"   "23"   "27"   "10"   "10"   "32"   "58"   "27"   "51"   "20"  
 [155] "20"   "55"   "19"   "30"   "0"    "43"   "46"   "25"   "25"   "50"   "40"   "17"   "35"   "45"  
 [169] "#N/A" "32"   "33"   "30"   "50"   "35"   "29"   "30"   "15"   "26"   "#N/A" "19"   "26"   "16"  
 [183] "21"   "33"   "30"   "33"   "61"   "11"   "22"   "29"   "21"   "0"    "34"   "12"   "34"   "31"  
 [197] "39"   "42"   "9"    "20"   "#N/A" "24"   "28"   "21"   "26"   "30"   "30"   "35"   "43"   "28"  
 [211] "35"   "41"   "40"   "20"   "25"   "50"   "30"   "20"   "20"   "23"   "40"   "35"   "22"   "60"  
 [225] "33"   "30"   "20"   "28"   "30"   "58"   "30"   "50"   "45"   "40"   "10"   "25"   "40"   "33"  
 [239] "20"   "26"   "25"   "26"   "43"   "#N/A" "#N/A" "56"   "21"   "#N/A" "40"   "45"   "50"   "46"  
 [253] "20"   "40"   "#N/A" "40"   "33"   "40"   "51"   "25"   "30"   "40"   "20"   "35"   "35"   "34"  
 [267] "38"   "28"   "20"   "70"   "20"   "24"   "43"   "50"   "12"   "22"   "18"   "51"   "50"   "25"  
 [281] "1"    "35"   "20"   "33"   "20"   "35"   "34"   "33"   "15"   "31"   "36"   "38"   "30"   "33"  
 [295] "12"   "45"   "34"   "40"   "35"   "55"   "19"   "39"   "19"   "#N/A" "27"   "20"   "35"   "40"  
 [309] "35"   "30"   "43"   "36"   "40"   "45"   "26"   "34"   "30"   "20"   "14"   "20"   "29"   "35"  
 [323] "42"   "37"   "9"    "20"   "32"   "0"    "30"   "35"   "45"   "50"   "50"   "25"   "#N/A" "34"  
 [337] "56"   "15"   "40"   "28"   "20"   "25"   "40"   "28"   "40"   "43"   "22"   "34"   "33"   "38"  
 [351] "53"   "29"   "16"   "45"   "33"   "31"   "18"   "39"   "20"   "9"    "25"   "15"   "25"   "40"  
 [365] "11"   "22"   "#N/A" "43"   "30"   "37"   "46"   "16"   "40"   "21"   "24"   "38"   "46"   "21"  
 [379] "23"   "35"   "45"   "55"   "30"   "34"   "30"   "11"   "55"   "11"   "29"   "23"   "26"   "8"   
 [393] "27"   "20"   "34"   "26"   "40"   "0"    "32"   "33"   "47"   "41"   "30"   "25"   "22"   "35"  
 [407] "5"    "25"   "30"   "18"   "18"   "36"   "29"   "34"   "30"   "30"   "21"   "26"   "45"   "15"  
 [421] "12"   "37"   "20"   "31"   "23"   "39"   "33"   "10"   "33"   "45"   "46"   "21"   "45"   "38"  
 [435] "24"   "30"   "20"   "11"   "16"   "30"   "10"   "33"   "40"   "24"   "32"   "55"   "30"   "20"  
 [449] "20"   "40"   "34"   "27"   "24"   "30"   "20"   "29"   "51"   "23"   "7"    "25"   "#N/A" "8"   
 [463] "50"   "40"   "35"   "38"   "34"   "38"   "26"   "69"   "10"   "35"   "19"   "31"   "20"   "32"  
 [477] "18"   "60"   "40"   "#N/A" "#N/A" "16"   "24"   "20"   "38"   "33"   "30"   "22"   "20"   "28"  
 [491] "45"   "#N/A" "53"   "11"   "35"   "22"   "44"   "22"   "27"   "40"   "36"   "31"   "47"   "68"  
 [505] "26"   "32"   "28"   "43"   "29"   "53"   "25"   "49"   "55"   "30"   "44"   "22"   "18"   "50"  
 [519] "49"   "18"   "40"   "25"   "44"   "30"   "18"   "0"    "25"   "26"   "50"   "#N/A" "31"   "30"  
 [533] "24"   "20"   "35"   "35"   "42"   "25"   "35"   "47"   "17"   "22"   "25"   "24"   "40"   "15"  
 [547] "39"   "20"   "14"   "52"   "23"   "25"   "31"   "12"   "25"   "30"   "45"   "41"   "21"   "44"  
 [561] "95"   "25"   "27"   "27"   "69"   "43"   "20"   "50"   "29"   "10"   "35"   "33"   "6"    "#N/A"
 [575] "42"   "35"   "60"   "45"   "28"   "20"   "#N/A" "20"   "14"   "27"   "29"   "30"   "31"   "40"  
 [589] "31"   "75"   "27"   "25"   "34"   "11"   "20"   "40"   "30"   "30"   "20"   "23"   "20"   "15"  
 [603] "10"   "37"   "35"   "28"   "45"   "17"   "30"   "36"   "42"   "10"   "21"   "0"    "33"   "38"  
 [617] "56"   "22"   "40"   "24"   "52"   "30"   "36"   "24"   "0"    "9"    "32"   "14"   "23"   "50"  
 [631] "29"   "25"   "40"   "20"   "55"   "25"   "35"   "38"   "25"   "15"   "33"   "4"    "29"   "24"  
 [645] "31"   "41"   "40"   "36"   "17"   "40"   "35"   "14"   "26"   "35"   "44"   "32"   "28"   "27"  
 [659] "30"   "32"   "25"   "20"   "40"   "34"   "60"   "20"   "50"   "27"   "8"    "55"   "28"   "18"  
 [673] "8"    "50"   "30"   "25"   "28"   "20"   "0"    "31"   "25"   "#N/A" "24"   "30"   "18"   "16"  
 [687] "#N/A" "30"   "1"    "38"   "5"    "17"   "7"    "32"   "50"   "10"   "35"   "10"   "55"   "20"  
 [701] "34"   "25"   "21"   "20"   "21"   "45"   "26"   "34"   "27"   "30"   "65"   "30"   "40"   "25"  
 [715] "50"   "3"    "20"   "30"   "45"   "10"   "31"   "#N/A" "48"   "30"   "46"   "30"   "40"   "40"  
 [729] "46"   "30"   "20"   "68"   "18"   "8"    "25"   "38"   "60"   "8"    "50"   "28"   "40"   "20"  
 [743] "33"   "50"   "50"   "30"   "15"   "33"   "81"   "15"   "28"   "32"   "#N/A" "27"   "32"   "36"  
 [757] "20"   "31"   "36"   "#N/A" "28"   "39"   "14"   "38"   "25"   "20"   "18"   "32"   "52"   "32"  
 [771] "10"   "45"   "69"   "21"   "50"   "29"   "40"   "21"   "47"   "30"   "20"   "42"   "39"   "38"  
 [785] "15"   "11"   "36"   "43"   "25"   "25"   "20"   "62"   "69"   "20"   "38"   "30"   "30"   "#N/A"
 [799] "52"   "50"   "40"   "45"   "50"   "40"   "28"   "30"   "30"   "#N/A" "30"   "25"   "20"   "13"  
 [813] "32"   "15"   "32"   "10"   "45"   "6"    "24"   "40"   "26"   "18"   "35"   "60"   "44"   "37"  
 [827] "27"   "26"   "18"   "40"   "22"   "40"   "40"   "30"   "21"   "36"   "27"   "55"   "20"   "30"  
 [841] "38"   "33"   "24"   "35"   "30"   "35"   "21"   "31"   "20"   "40"   "25"   "32"   "39"   "35"  
 [855] "43"   "28"   "37"   "24"   "12"   "36"   "40"   "71"   "50"   "34"   "45"   "0"    "10"   "55"  
 [869] "56"   "30"   "40"   "13"   "22"   "23"   "32"   "30"   "30"   "33"   "20"   "40"   "44"   "32"  
 [883] "15"   "39"   "#N/A" "45"   "32"   "20"   "32"   "31"   "25"   "30"   "#N/A" "40"   "30"   "30"  
 [897] "29"   "37"   "31"   "28"   "34"   "32"   "40"   "28"   "50"   "31"   "23"   "25"   "32"   "45"  
 [911] "22"   "33"   "30"   "18"   "38"   "17"   "30"   "35"   "30"   "25"   "37"   "51"   "38"   "10"  
 [925] "55"   "27"   "21"   "40"   "47"   "56"   "23"   "40"   "37"   "45"   "23"   "26"   "38"   "45"  
 [939] "7"    "45"   "35"   "40"   "20"   "23"   "20"   "23"   "6"    "33"   "40"   "30"   "38"   "57"  
 [953] "30"   "10"   "28"   "33"   "4"    "20"   "25"   "27"   "15"   "60"   "65"   "64"   "65"   "50"  
 [967] "33"   "20"   "30"   "38"   "15"   "60"   "60"   "38"   "40"   "20"   "27"   "45"   "6"    "14"  
 [981] "33"   "37"   "35"   "12"   "25"   "35"   "27"   "30"   "#N/A" "45"   "20"   "38"   "43"   "20"  
 [995] "#N/A" "28"   "9"    "27"   "19"   "23"   "26"   "#N/A" "50"   "23"   "50"   "30"   "8"    "23"  
[1009] "20"   "19"   "30"   "40"   "35"   "29"   "55"   "33"   "6"    "35"   "0"    "40"   "30"   "#N/A"
[1023] "20"   "40"   "46"   "27"   "43"   "40"   "33"   "40"   "42"   "45"   "40"   "35"   "30"   "36"  
[1037] "19"   "30"   "43"   "8"    "40"   "32"   "65"   "30"   "44"   "26"   "73"   "24"   "30"   "39"  
[1051] "16"   "37"   "30"   "#N/A" "20"   "27"   "27"   "36"   "20"   "35"   "38"   "26"   "36"   "17"  
[1065] "21"   "55"   "22"   "45"   "39"   "22"   "18"   "15"   "#N/A" "20"   "27"   "0"    "28"   "25"  
[1079] "64"   "40"   "11"   "25"   "11"   "37"   "10"   "43"   "20"   "38"   "17"   "50"   "44"   "35"  
[1093] "23"   "35"   "22"   "20"   "15"   "35"   "30"   "50"   "0"    "71"   "48"   "25"   "33"   "30"  
[1107] "60"   "40"   "28"   "23"   "10"   "60"   "42"   "40"   "8"    "40"   "40"   "#N/A" "18"   "17"  
[1121] "25"   "18"   "32"   "27"   "30"   "48"   "20"   "0"    "25"   "41"   "12"   "25"   "40"   "37"  
[1135] "45"   "43"   "50"   "#N/A" "10"   "19"   "41"   "45"   "0"    "25"   "30"   "70"   "30"   "40"  
[1149] "30"   "34"   "24"   "40"   "40"   "30"   "12"   "23"   "52"   "33"   "29"   "32"   "35"   "20"  
[1163] "15"   "51"   "22"   "25"   "46"   "28"   "37"   "28"   "25"   "42"   "15"   "50"   "25"   "14"  
[1177] "15"   "14"   "27"   "40"   "36"   "20"   "32"   "33"   "40"   "33"   "19"   "31"   "21"   "25"  
[1191] "28"   "33"   "20"   "0"    "12"   "20"   "30"   "23"   "30"   "10"   "40"   "35"   "30"   "43"  
[1205] "48"   "38"   "#N/A" "11"   "58"   "20"   "15"   "61"   "20"   "67"   "25"   "40"   "37"   "30"  
[1219] "23"   "25"   "23"   "30"   "0"    "30"   "20"   "41"   "33"   "15"   "17"   "22"   "32"   "20"  
[1233] "27"   "71"   "25"   "32"   "15"   "30"   "36"   "8"    "16"   "20"   "25"   "26"   "0"    "60"  
[1247] "5"    "19"   "19"   "30"   "14"   "20"   "6"    "10"   "22"   "34"   "11"   "12"   "27"   "10"  
[1261] "55"   "14"   "8"    "65"   "28"   "25"   "49"   "35"   "40"   "20"   "10"   "60"   "10"   "20"  
[1275] "30"   "35"   "30"   "25"   "20"   "15"   "72"   "35"   "27"   "7"    "26"   "17"   "45"   "13"  
[1289] "29"   "28"   "15"   "20"   "41"   "30"   "65"   "50"   "35"   "36"   "28"   "45"   "50"   "30"  
[1303] "45"   "30"   "30"   "35"   "30"   "15"   "16"   "55"   "29"   "30"   "34"   "15"   "61"   "27"  
[1317] "16"   "14"   "25"   "25"   "33"   "30"   "42"   "30"   "32"   "40"   "30"   "25"   "9"    "40"  
[1331] "28"   "13"   "41"   "35"   "42"   "10"   "85"   "70"   "26"   "27"   "35"   "20"   "22"   "20"  
[1345] "1"    "28"   "6"    "5"    "42"   "20"   "20"   "24"   "25"   "35"   "20"   "15"   "20"   "37"  
[1359] "30"   "30"   "30"   "10"   "#N/A" "51"   "25"   "22"   "22"   "0"    "20"   "60"   "23"   "26"  
[1373] "15"   "35"   "15"   "19"   "28"   "20"   "15"   "10"   "18"   "25"   "30"   "20"   "5"    "#N/A"
[1387] "21"   "45"   "29"   "48"   "10"   "27"   "#N/A" "32"   "25"   "21"   "30"   "60"   "60"   "19"  
[1401] "20"   "29"   "5"    "47"   "14"   "46"   "46"   "48"   "22"   "42"   "19"   "48"   "27"   "32"  
[1415] "31"   "42"   "64"   "22"   "25"   "24"   "30"   "60"   "56"   "20"   "45"   "45"   "33"   "31"  
[1429] "#N/A" "50"   "29"   "41"   "22"   "35"   "25"   "27"   "26"   "40"   "38"   "42"   "40"   "20"  
[1443] "23"   "15"   "30"   "55"   "35"   "29"   "30"   "32"  

Use the na argument to specify allowed NA values

NCbirths <- read_csv(
  "https://wilkelab.org/SDS366/datasets/NCbirths.csv",
  na = c("", "NA", "#N/A")
)

NCbirths
# A tibble: 1,450 × 15
      ID Plural   Sex MomAge Weeks Marital RaceMom HispMom Gained Smoke BirthWeightOz BirthWeightGm   Low
   <dbl>  <dbl> <dbl>  <dbl> <dbl>   <dbl>   <dbl> <chr>    <dbl> <dbl>         <dbl>         <dbl> <dbl>
 1     1      1     1     32    40       1       1 N           38     0           111         3147.     0
 2     2      1     2     32    37       1       1 N           34     0           116         3289.     0
 3     3      1     1     27    39       1       1 N           12     0           138         3912.     0
 4     4      1     1     27    39       1       1 N           15     0           136         3856.     0
 5     5      1     1     25    39       1       1 N           32     0           121         3430.     0
 6     6      1     1     28    43       1       1 N           32     0           117         3317.     0
 7     7      1     2     25    39       1       1 N           75     0           143         4054.     0
 8     8      1     2     15    42       2       1 N           25     0           113         3204.     0
 9     9      1     2     21    39       1       1 N           28     0           120         3402      0
10    10      1     2     27    40       2       1 N           37     0           124         3515.     0
# ℹ 1,440 more rows
# ℹ 2 more variables: Premie <dbl>, MomRace <chr>

Use the na argument to specify allowed NA values

NCbirths <- read_csv(
  "https://wilkelab.org/SDS366/datasets/NCbirths.csv",
  na = c("", "NA", "#N/A")
)

NCbirths |>
  pull(Gained)
   [1] 38 34 12 15 32 32 75 25 28 37 45 52 26 31 40 51 45 25  0 20 20 38 15  3  9 37 30 40 37 56 48  4 43 40
  [35] 25 53 15 19 26 32 25 50 34  2 23 16 48 80 19 16 50 55 25 33 10 30 30 NA 55 38 33 49 14 18 40 30 17 45
  [69] 15 31 50 25 12 38 47 20 40 34  5 25 18 27 46 31 48 15 51 12 33 17 25 31 24 16 18 40 16 57 18 29 45 18
 [103] 11 20 50 26 20 35 12 38 50 28 34 41 20  5 30 35 16 32 40 30 28 25 50 25  0  7 24 34 40 32 25 25 25  0
 [137] 47 45 34 46 40 38  0 35 10 23 27 10 10 32 58 27 51 20 20 55 19 30  0 43 46 25 25 50 40 17 35 45 NA 32
 [171] 33 30 50 35 29 30 15 26 NA 19 26 16 21 33 30 33 61 11 22 29 21  0 34 12 34 31 39 42  9 20 NA 24 28 21
 [205] 26 30 30 35 43 28 35 41 40 20 25 50 30 20 20 23 40 35 22 60 33 30 20 28 30 58 30 50 45 40 10 25 40 33
 [239] 20 26 25 26 43 NA NA 56 21 NA 40 45 50 46 20 40 NA 40 33 40 51 25 30 40 20 35 35 34 38 28 20 70 20 24
 [273] 43 50 12 22 18 51 50 25  1 35 20 33 20 35 34 33 15 31 36 38 30 33 12 45 34 40 35 55 19 39 19 NA 27 20
 [307] 35 40 35 30 43 36 40 45 26 34 30 20 14 20 29 35 42 37  9 20 32  0 30 35 45 50 50 25 NA 34 56 15 40 28
 [341] 20 25 40 28 40 43 22 34 33 38 53 29 16 45 33 31 18 39 20  9 25 15 25 40 11 22 NA 43 30 37 46 16 40 21
 [375] 24 38 46 21 23 35 45 55 30 34 30 11 55 11 29 23 26  8 27 20 34 26 40  0 32 33 47 41 30 25 22 35  5 25
 [409] 30 18 18 36 29 34 30 30 21 26 45 15 12 37 20 31 23 39 33 10 33 45 46 21 45 38 24 30 20 11 16 30 10 33
 [443] 40 24 32 55 30 20 20 40 34 27 24 30 20 29 51 23  7 25 NA  8 50 40 35 38 34 38 26 69 10 35 19 31 20 32
 [477] 18 60 40 NA NA 16 24 20 38 33 30 22 20 28 45 NA 53 11 35 22 44 22 27 40 36 31 47 68 26 32 28 43 29 53
 [511] 25 49 55 30 44 22 18 50 49 18 40 25 44 30 18  0 25 26 50 NA 31 30 24 20 35 35 42 25 35 47 17 22 25 24
 [545] 40 15 39 20 14 52 23 25 31 12 25 30 45 41 21 44 95 25 27 27 69 43 20 50 29 10 35 33  6 NA 42 35 60 45
 [579] 28 20 NA 20 14 27 29 30 31 40 31 75 27 25 34 11 20 40 30 30 20 23 20 15 10 37 35 28 45 17 30 36 42 10
 [613] 21  0 33 38 56 22 40 24 52 30 36 24  0  9 32 14 23 50 29 25 40 20 55 25 35 38 25 15 33  4 29 24 31 41
 [647] 40 36 17 40 35 14 26 35 44 32 28 27 30 32 25 20 40 34 60 20 50 27  8 55 28 18  8 50 30 25 28 20  0 31
 [681] 25 NA 24 30 18 16 NA 30  1 38  5 17  7 32 50 10 35 10 55 20 34 25 21 20 21 45 26 34 27 30 65 30 40 25
 [715] 50  3 20 30 45 10 31 NA 48 30 46 30 40 40 46 30 20 68 18  8 25 38 60  8 50 28 40 20 33 50 50 30 15 33
 [749] 81 15 28 32 NA 27 32 36 20 31 36 NA 28 39 14 38 25 20 18 32 52 32 10 45 69 21 50 29 40 21 47 30 20 42
 [783] 39 38 15 11 36 43 25 25 20 62 69 20 38 30 30 NA 52 50 40 45 50 40 28 30 30 NA 30 25 20 13 32 15 32 10
 [817] 45  6 24 40 26 18 35 60 44 37 27 26 18 40 22 40 40 30 21 36 27 55 20 30 38 33 24 35 30 35 21 31 20 40
 [851] 25 32 39 35 43 28 37 24 12 36 40 71 50 34 45  0 10 55 56 30 40 13 22 23 32 30 30 33 20 40 44 32 15 39
 [885] NA 45 32 20 32 31 25 30 NA 40 30 30 29 37 31 28 34 32 40 28 50 31 23 25 32 45 22 33 30 18 38 17 30 35
 [919] 30 25 37 51 38 10 55 27 21 40 47 56 23 40 37 45 23 26 38 45  7 45 35 40 20 23 20 23  6 33 40 30 38 57
 [953] 30 10 28 33  4 20 25 27 15 60 65 64 65 50 33 20 30 38 15 60 60 38 40 20 27 45  6 14 33 37 35 12 25 35
 [987] 27 30 NA 45 20 38 43 20 NA 28  9 27 19 23 26 NA 50 23 50 30  8 23 20 19 30 40 35 29 55 33  6 35  0 40
[1021] 30 NA 20 40 46 27 43 40 33 40 42 45 40 35 30 36 19 30 43  8 40 32 65 30 44 26 73 24 30 39 16 37 30 NA
[1055] 20 27 27 36 20 35 38 26 36 17 21 55 22 45 39 22 18 15 NA 20 27  0 28 25 64 40 11 25 11 37 10 43 20 38
[1089] 17 50 44 35 23 35 22 20 15 35 30 50  0 71 48 25 33 30 60 40 28 23 10 60 42 40  8 40 40 NA 18 17 25 18
[1123] 32 27 30 48 20  0 25 41 12 25 40 37 45 43 50 NA 10 19 41 45  0 25 30 70 30 40 30 34 24 40 40 30 12 23
[1157] 52 33 29 32 35 20 15 51 22 25 46 28 37 28 25 42 15 50 25 14 15 14 27 40 36 20 32 33 40 33 19 31 21 25
[1191] 28 33 20  0 12 20 30 23 30 10 40 35 30 43 48 38 NA 11 58 20 15 61 20 67 25 40 37 30 23 25 23 30  0 30
[1225] 20 41 33 15 17 22 32 20 27 71 25 32 15 30 36  8 16 20 25 26  0 60  5 19 19 30 14 20  6 10 22 34 11 12
[1259] 27 10 55 14  8 65 28 25 49 35 40 20 10 60 10 20 30 35 30 25 20 15 72 35 27  7 26 17 45 13 29 28 15 20
[1293] 41 30 65 50 35 36 28 45 50 30 45 30 30 35 30 15 16 55 29 30 34 15 61 27 16 14 25 25 33 30 42 30 32 40
[1327] 30 25  9 40 28 13 41 35 42 10 85 70 26 27 35 20 22 20  1 28  6  5 42 20 20 24 25 35 20 15 20 37 30 30
[1361] 30 10 NA 51 25 22 22  0 20 60 23 26 15 35 15 19 28 20 15 10 18 25 30 20  5 NA 21 45 29 48 10 27 NA 32
[1395] 25 21 30 60 60 19 20 29  5 47 14 46 46 48 22 42 19 48 27 32 31 42 64 22 25 24 30 60 56 20 45 45 33 31
[1429] NA 50 29 41 22 35 25 27 26 40 38 42 40 20 23 15 30 55 35 29 30 32

Detailed quality checks: Look at all column names

 [1] "ID"            "Plural"        "Sex"           "MomAge"       
 [5] "Weeks"         "Marital"       "RaceMom"       "HispMom"      
 [9] "Gained"        "Smoke"         "BirthWeightOz" "BirthWeightGm"
[13] "Low"           "Premie"        "MomRace"      

What’s the difference between RaceMom and MomRace?

Detailed quality checks: Look at all column names

From the data dictionary:

  • RaceMom
    Mother’s race: 1=white, 2=black, 3=American Indian, 4=Chinese, 5=Japanese, 6=Hawaiian, 7=Filipino, or 8=Other Asian or Pacific Islander

  • MomRace
    Mother’s race: black, hispanic, other, or white

These are similar but not the same. Important not to confuse them!

Detailed quality checks: Look at every data column

summary(NCbirths$ID) # five number summary
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
    1.0   363.2   725.5   725.5  1087.8  1450.0 


unique(NCbirths$ID)  # all unique values
   [1]    1    2    3    4    5    6    7    8
   [9]    9   10   11   12   13   14   15   16
  [17]   17   18   19   20   21   22   23   24
  [25]   25   26   27   28   29   30   31   32
  [33]   33   34   35   36   37   38   39   40
  [41]   41   42   43   44   45   46   47   48
  [49]   49   50   51   52   53   54   55   56
  [57]   57   58   59   60   61   62   63   64
  [65]   65   66   67   68   69   70   71   72
  [73]   73   74   75   76   77   78   79   80
  [81]   81   82   83   84   85   86   87   88
  [89]   89   90   91   92   93   94   95   96
  [97]   97   98   99  100  101  102  103  104
 [105]  105  106  107  108  109  110  111  112
 [113]  113  114  115  116  117  118  119  120
 [121]  121  122  123  124  125  126  127  128
 [129]  129  130  131  132  133  134  135  136
 [137]  137  138  139  140  141  142  143  144
 [145]  145  146  147  148  149  150  151  152
 [153]  153  154  155  156  157  158  159  160
 [161]  161  162  163  164  165  166  167  168
 [169]  169  170  171  172  173  174  175  176
 [177]  177  178  179  180  181  182  183  184
 [185]  185  186  187  188  189  190  191  192
 [193]  193  194  195  196  197  198  199  200
 [201]  201  202  203  204  205  206  207  208
 [209]  209  210  211  212  213  214  215  216
 [217]  217  218  219  220  221  222  223  224
 [225]  225  226  227  228  229  230  231  232
 [233]  233  234  235  236  237  238  239  240
 [241]  241  242  243  244  245  246  247  248
 [249]  249  250  251  252  253  254  255  256
 [257]  257  258  259  260  261  262  263  264
 [265]  265  266  267  268  269  270  271  272
 [273]  273  274  275  276  277  278  279  280
 [281]  281  282  283  284  285  286  287  288
 [289]  289  290  291  292  293  294  295  296
 [297]  297  298  299  300  301  302  303  304
 [305]  305  306  307  308  309  310  311  312
 [313]  313  314  315  316  317  318  319  320
 [321]  321  322  323  324  325  326  327  328
 [329]  329  330  331  332  333  334  335  336
 [337]  337  338  339  340  341  342  343  344
 [345]  345  346  347  348  349  350  351  352
 [353]  353  354  355  356  357  358  359  360
 [361]  361  362  363  364  365  366  367  368
 [369]  369  370  371  372  373  374  375  376
 [377]  377  378  379  380  381  382  383  384
 [385]  385  386  387  388  389  390  391  392
 [393]  393  394  395  396  397  398  399  400
 [401]  401  402  403  404  405  406  407  408
 [409]  409  410  411  412  413  414  415  416
 [417]  417  418  419  420  421  422  423  424
 [425]  425  426  427  428  429  430  431  432
 [433]  433  434  435  436  437  438  439  440
 [441]  441  442  443  444  445  446  447  448
 [449]  449  450  451  452  453  454  455  456
 [457]  457  458  459  460  461  462  463  464
 [465]  465  466  467  468  469  470  471  472
 [473]  473  474  475  476  477  478  479  480
 [481]  481  482  483  484  485  486  487  488
 [489]  489  490  491  492  493  494  495  496
 [497]  497  498  499  500  501  502  503  504
 [505]  505  506  507  508  509  510  511  512
 [513]  513  514  515  516  517  518  519  520
 [521]  521  522  523  524  525  526  527  528
 [529]  529  530  531  532  533  534  535  536
 [537]  537  538  539  540  541  542  543  544
 [545]  545  546  547  548  549  550  551  552
 [553]  553  554  555  556  557  558  559  560
 [561]  561  562  563  564  565  566  567  568
 [569]  569  570  571  572  573  574  575  576
 [577]  577  578  579  580  581  582  583  584
 [585]  585  586  587  588  589  590  591  592
 [593]  593  594  595  596  597  598  599  600
 [601]  601  602  603  604  605  606  607  608
 [609]  609  610  611  612  613  614  615  616
 [617]  617  618  619  620  621  622  623  624
 [625]  625  626  627  628  629  630  631  632
 [633]  633  634  635  636  637  638  639  640
 [641]  641  642  643  644  645  646  647  648
 [649]  649  650  651  652  653  654  655  656
 [657]  657  658  659  660  661  662  663  664
 [665]  665  666  667  668  669  670  671  672
 [673]  673  674  675  676  677  678  679  680
 [681]  681  682  683  684  685  686  687  688
 [689]  689  690  691  692  693  694  695  696
 [697]  697  698  699  700  701  702  703  704
 [705]  705  706  707  708  709  710  711  712
 [713]  713  714  715  716  717  718  719  720
 [721]  721  722  723  724  725  726  727  728
 [729]  729  730  731  732  733  734  735  736
 [737]  737  738  739  740  741  742  743  744
 [745]  745  746  747  748  749  750  751  752
 [753]  753  754  755  756  757  758  759  760
 [761]  761  762  763  764  765  766  767  768
 [769]  769  770  771  772  773  774  775  776
 [777]  777  778  779  780  781  782  783  784
 [785]  785  786  787  788  789  790  791  792
 [793]  793  794  795  796  797  798  799  800
 [801]  801  802  803  804  805  806  807  808
 [809]  809  810  811  812  813  814  815  816
 [817]  817  818  819  820  821  822  823  824
 [825]  825  826  827  828  829  830  831  832
 [833]  833  834  835  836  837  838  839  840
 [841]  841  842  843  844  845  846  847  848
 [849]  849  850  851  852  853  854  855  856
 [857]  857  858  859  860  861  862  863  864
 [865]  865  866  867  868  869  870  871  872
 [873]  873  874  875  876  877  878  879  880
 [881]  881  882  883  884  885  886  887  888
 [889]  889  890  891  892  893  894  895  896
 [897]  897  898  899  900  901  902  903  904
 [905]  905  906  907  908  909  910  911  912
 [913]  913  914  915  916  917  918  919  920
 [921]  921  922  923  924  925  926  927  928
 [929]  929  930  931  932  933  934  935  936
 [937]  937  938  939  940  941  942  943  944
 [945]  945  946  947  948  949  950  951  952
 [953]  953  954  955  956  957  958  959  960
 [961]  961  962  963  964  965  966  967  968
 [969]  969  970  971  972  973  974  975  976
 [977]  977  978  979  980  981  982  983  984
 [985]  985  986  987  988  989  990  991  992
 [993]  993  994  995  996  997  998  999 1000
[1001] 1001 1002 1003 1004 1005 1006 1007 1008
[1009] 1009 1010 1011 1012 1013 1014 1015 1016
[1017] 1017 1018 1019 1020 1021 1022 1023 1024
[1025] 1025 1026 1027 1028 1029 1030 1031 1032
[1033] 1033 1034 1035 1036 1037 1038 1039 1040
[1041] 1041 1042 1043 1044 1045 1046 1047 1048
[1049] 1049 1050 1051 1052 1053 1054 1055 1056
[1057] 1057 1058 1059 1060 1061 1062 1063 1064
[1065] 1065 1066 1067 1068 1069 1070 1071 1072
[1073] 1073 1074 1075 1076 1077 1078 1079 1080
[1081] 1081 1082 1083 1084 1085 1086 1087 1088
[1089] 1089 1090 1091 1092 1093 1094 1095 1096
[1097] 1097 1098 1099 1100 1101 1102 1103 1104
[1105] 1105 1106 1107 1108 1109 1110 1111 1112
[1113] 1113 1114 1115 1116 1117 1118 1119 1120
[1121] 1121 1122 1123 1124 1125 1126 1127 1128
[1129] 1129 1130 1131 1132 1133 1134 1135 1136
[1137] 1137 1138 1139 1140 1141 1142 1143 1144
[1145] 1145 1146 1147 1148 1149 1150 1151 1152
[1153] 1153 1154 1155 1156 1157 1158 1159 1160
[1161] 1161 1162 1163 1164 1165 1166 1167 1168
[1169] 1169 1170 1171 1172 1173 1174 1175 1176
[1177] 1177 1178 1179 1180 1181 1182 1183 1184
[1185] 1185 1186 1187 1188 1189 1190 1191 1192
[1193] 1193 1194 1195 1196 1197 1198 1199 1200
[1201] 1201 1202 1203 1204 1205 1206 1207 1208
[1209] 1209 1210 1211 1212 1213 1214 1215 1216
[1217] 1217 1218 1219 1220 1221 1222 1223 1224
[1225] 1225 1226 1227 1228 1229 1230 1231 1232
[1233] 1233 1234 1235 1236 1237 1238 1239 1240
[1241] 1241 1242 1243 1244 1245 1246 1247 1248
[1249] 1249 1250 1251 1252 1253 1254 1255 1256
[1257] 1257 1258 1259 1260 1261 1262 1263 1264
[1265] 1265 1266 1267 1268 1269 1270 1271 1272
[1273] 1273 1274 1275 1276 1277 1278 1279 1280
[1281] 1281 1282 1283 1284 1285 1286 1287 1288
[1289] 1289 1290 1291 1292 1293 1294 1295 1296
[1297] 1297 1298 1299 1300 1301 1302 1303 1304
[1305] 1305 1306 1307 1308 1309 1310 1311 1312
[1313] 1313 1314 1315 1316 1317 1318 1319 1320
[1321] 1321 1322 1323 1324 1325 1326 1327 1328
[1329] 1329 1330 1331 1332 1333 1334 1335 1336
[1337] 1337 1338 1339 1340 1341 1342 1343 1344
[1345] 1345 1346 1347 1348 1349 1350 1351 1352
[1353] 1353 1354 1355 1356 1357 1358 1359 1360
[1361] 1361 1362 1363 1364 1365 1366 1367 1368
[1369] 1369 1370 1371 1372 1373 1374 1375 1376
[1377] 1377 1378 1379 1380 1381 1382 1383 1384
[1385] 1385 1386 1387 1388 1389 1390 1391 1392
[1393] 1393 1394 1395 1396 1397 1398 1399 1400
[1401] 1401 1402 1403 1404 1405 1406 1407 1408
[1409] 1409 1410 1411 1412 1413 1414 1415 1416
[1417] 1417 1418 1419 1420 1421 1422 1423 1424
[1425] 1425 1426 1427 1428 1429 1430 1431 1432
[1433] 1433 1434 1435 1436 1437 1438 1439 1440
[1441] 1441 1442 1443 1444 1445 1446 1447 1448
[1449] 1449 1450
# histogram
ggplot(NCbirths, aes(ID)) +
  geom_histogram()

 

Detailed quality checks: Look at every data column

summary(NCbirths$Plural) # five number summary
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  1.000   1.000   1.000   1.037   1.000   3.000 


unique(NCbirths$Plural)  # all unique values
[1] 1 2 3
# histogram
ggplot(NCbirths, aes(Plural)) +
  geom_histogram()

 

Detailed quality checks: Look at every data column

summary(NCbirths$Weeks) # five number summary
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
-999.00   38.00   39.00   37.91   40.00   45.00 


unique(NCbirths$Weeks)  # all unique values
 [1]   40   37   39   43   42   41   36   38   30
[10]   31   45   33   34   44   32   35   24   27
[19]   23   29   25   28   22 -999   26
# histogram
ggplot(NCbirths, aes(Weeks)) +
  geom_histogram()

 

What is the meaning of -999 weeks?

In some cases, nonsensical values indicate missingness

We need to make sure to catch those cases:

library(naniar) # library for handling missing values

NCbirths <- read_csv(
  "https://wilkelab.org/SDS366/datasets/NCbirths.csv",
  na = c("", "NA", "#N/A")
) |> replace_with_na_at("Weeks", ~.x < 0) # recode negative weeks to NA


summary(NCbirths$Weeks)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's 
  22.00   38.00   39.00   38.62   40.00   45.00       1 


unique(NCbirths$Weeks)
 [1] 40 37 39 43 42 41 36 38 30 31 45 33 34 44 32 35 24 27 23 29 25 28 22
[24] NA 26

In some cases, nonsensical values indicate missingness

Before recoding -999 to NA:

ggplot(NCbirths, aes(Weeks)) +
  geom_histogram()

 

After recoding -999 to NA:

ggplot(NCbirths, aes(Weeks)) +
  geom_histogram()

 

Consider recoding categorical variables

Sex of the baby is encoded as 1/2:

NCbirths |>
  pull(Sex)
   [1] 1 2 1 1 1 1 2 2 2 2 1 2 2 2 2 1 1 1 1 1 2 2 2 2 2 1 2 2 1 2 1 2 2 1
  [35] 2 2 1 2 1 2 2 1 2 1 1 1 2 1 1 2 2 1 2 2 2 1 1 2 1 2 1 2 1 2 2 1 1 2
  [69] 1 1 2 2 1 1 2 2 1 1 2 1 2 2 2 1 1 1 2 2 2 1 1 1 1 1 1 1 1 2 2 1 1 1
 [103] 1 2 2 1 2 1 2 1 1 2 1 2 1 1 2 2 1 1 2 1 2 1 2 1 1 2 2 1 1 1 2 2 2 1
 [137] 1 1 1 2 1 1 2 1 1 1 1 2 2 1 1 1 1 2 2 2 2 2 2 2 1 2 1 1 1 1 1 2 2 2
 [171] 1 1 1 1 2 1 2 1 1 1 2 2 2 2 2 1 2 1 2 1 2 2 1 2 1 1 1 1 2 2 1 1 2 1
 [205] 2 1 1 2 1 2 1 1 1 1 1 2 1 2 2 1 2 2 1 1 2 2 2 2 1 2 1 2 1 1 1 1 2 2
 [239] 2 1 2 2 2 2 2 2 1 1 2 1 2 1 2 2 1 2 2 1 1 2 2 1 1 1 2 2 1 2 2 1 2 1
 [273] 2 1 1 1 1 1 2 2 1 1 1 1 2 1 1 1 2 2 2 2 1 2 1 2 2 1 1 2 1 1 1 1 1 2
 [307] 2 2 1 2 2 1 1 1 1 2 1 1 2 1 2 1 2 1 2 2 2 1 2 2 2 1 1 1 2 2 1 2 1 2
 [341] 1 2 1 1 1 2 1 1 1 2 2 1 2 2 2 2 1 1 1 2 1 2 1 2 1 2 1 1 2 2 2 2 1 2
 [375] 1 2 1 2 2 1 1 2 2 1 2 2 2 1 2 1 1 2 2 1 2 2 2 1 2 1 2 2 2 2 2 2 2 1
 [409] 1 2 2 1 1 1 1 2 1 1 1 1 1 1 1 2 1 2 2 2 1 2 1 2 2 1 1 2 2 2 1 1 2 2
 [443] 1 2 1 2 1 1 1 2 1 2 1 1 2 1 1 2 1 2 2 1 2 2 2 2 2 1 2 1 1 2 1 1 2 2
 [477] 1 2 2 2 2 1 2 1 1 1 2 1 1 1 1 2 1 1 2 1 2 1 1 1 2 2 2 1 2 2 1 1 1 2
 [511] 2 2 1 2 1 2 1 2 2 2 1 1 1 1 2 1 1 1 2 2 1 1 1 1 2 2 1 1 1 2 2 1 2 1
 [545] 2 1 1 1 2 2 2 1 1 1 1 2 2 1 2 2 1 2 2 1 1 2 2 1 1 1 2 2 1 2 1 1 1 2
 [579] 1 1 1 1 2 2 1 1 1 2 2 1 1 2 1 2 2 1 1 1 2 1 1 2 1 1 2 2 1 2 1 1 1 1
 [613] 2 2 2 1 2 1 2 1 1 2 1 1 1 2 2 1 1 2 1 2 2 2 2 2 1 1 2 1 1 2 1 2 2 1
 [647] 1 2 2 1 2 2 1 1 1 2 2 2 2 2 1 2 1 1 1 2 1 2 1 1 2 2 1 2 1 1 2 2 2 1
 [681] 2 1 2 2 1 2 2 2 2 2 1 2 1 1 1 2 1 2 2 1 2 2 1 2 1 2 1 2 1 2 2 2 1 1
 [715] 2 2 1 2 1 1 1 1 2 2 1 2 1 1 1 2 2 2 2 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
 [749] 1 2 1 1 1 1 2 2 2 1 2 2 2 2 1 2 1 1 1 2 2 1 2 2 1 1 2 1 1 1 2 2 2 2
 [783] 2 2 2 2 1 2 2 2 1 1 2 1 1 2 1 1 2 2 1 2 1 1 2 1 2 1 2 2 2 2 2 2 1 1
 [817] 1 1 2 1 1 2 2 1 1 2 1 1 2 1 2 1 1 2 1 2 2 1 1 1 2 1 2 2 2 2 1 1 1 2
 [851] 1 1 1 1 1 2 2 1 2 1 1 2 1 1 2 1 1 2 1 1 2 2 2 1 1 1 2 1 2 2 1 2 2 1
 [885] 1 2 1 1 1 1 2 2 2 1 2 2 1 1 2 2 2 1 2 1 1 1 2 1 1 2 2 2 1 2 1 1 1 2
 [919] 1 1 1 1 1 1 1 2 2 1 1 2 1 1 1 1 2 1 2 1 2 1 1 2 1 2 1 2 2 1 2 1 2 2
 [953] 1 2 2 1 2 1 2 1 2 1 2 2 1 1 2 2 1 2 1 2 1 2 2 2 1 2 2 1 1 2 2 1 2 1
 [987] 1 2 1 2 1 1 2 2 1 1 2 2 1 1 1 1 1 1 1 1 1 2 2 2 2 1 2 1 2 1 1 2 1 2
[1021] 1 1 1 2 2 1 1 1 2 2 1 2 1 2 2 1 1 1 2 2 1 2 1 1 2 1 1 1 2 2 1 1 1 2
[1055] 2 2 2 2 1 1 1 2 1 2 2 1 2 2 2 1 2 2 2 1 2 2 1 2 1 1 1 1 1 1 1 2 2 1
[1089] 2 1 1 2 1 2 2 1 2 2 2 2 2 2 2 1 1 2 1 1 2 2 1 2 1 1 2 2 1 1 1 2 2 1
[1123] 1 2 2 1 1 2 1 2 1 1 1 2 2 2 1 1 2 1 1 1 2 1 1 1 2 2 1 2 1 2 1 2 2 2
[1157] 1 1 1 2 2 1 1 1 1 2 2 2 2 1 2 1 2 2 2 2 1 1 1 2 1 1 1 2 2 2 2 1 2 1
[1191] 2 1 1 1 1 1 2 2 2 2 1 1 1 2 1 2 1 2 1 1 1 2 1 1 2 2 2 1 2 2 2 1 2 1
[1225] 2 1 2 1 1 2 1 1 1 2 1 2 1 1 1 2 2 2 2 1 1 2 2 1 2 2 1 1 2 1 1 2 1 2
[1259] 2 1 1 2 1 2 1 2 1 1 2 1 2 1 2 2 1 1 2 1 2 1 1 2 1 2 2 2 1 1 1 2 1 1
[1293] 2 2 2 1 2 1 1 2 2 2 2 1 1 1 2 1 1 1 1 2 2 1 1 2 1 1 2 2 2 1 2 2 2 2
[1327] 1 2 1 1 2 2 1 2 1 1 2 2 2 1 2 1 1 1 2 1 1 1 2 2 2 1 1 2 1 1 1 1 2 1
[1361] 1 2 1 2 1 1 2 2 2 1 1 1 1 1 1 1 1 1 2 1 2 1 2 2 2 1 2 2 1 1 2 1 1 2
[1395] 2 1 1 2 2 2 1 2 1 2 2 1 2 1 2 2 1 1 2 1 1 1 2 1 2 2 2 2 1 2 2 1 2 2
[1429] 2 1 1 1 2 2 1 1 1 1 1 2 1 2 2 2 2 2 2 2 1 2

Consider recoding categorical variables

Recode as "male"/"female":

NCbirths |>
  mutate(
    Sex = if_else(Sex == 1, "male", "female")
  ) |>
  pull(Sex)
   [1] "male"   "female" "male"   "male"   "male"   "male"   "female"
   [8] "female" "female" "female" "male"   "female" "female" "female"
  [15] "female" "male"   "male"   "male"   "male"   "male"   "female"
  [22] "female" "female" "female" "female" "male"   "female" "female"
  [29] "male"   "female" "male"   "female" "female" "male"   "female"
  [36] "female" "male"   "female" "male"   "female" "female" "male"  
  [43] "female" "male"   "male"   "male"   "female" "male"   "male"  
  [50] "female" "female" "male"   "female" "female" "female" "male"  
  [57] "male"   "female" "male"   "female" "male"   "female" "male"  
  [64] "female" "female" "male"   "male"   "female" "male"   "male"  
  [71] "female" "female" "male"   "male"   "female" "female" "male"  
  [78] "male"   "female" "male"   "female" "female" "female" "male"  
  [85] "male"   "male"   "female" "female" "female" "male"   "male"  
  [92] "male"   "male"   "male"   "male"   "male"   "male"   "female"
  [99] "female" "male"   "male"   "male"   "male"   "female" "female"
 [106] "male"   "female" "male"   "female" "male"   "male"   "female"
 [113] "male"   "female" "male"   "male"   "female" "female" "male"  
 [120] "male"   "female" "male"   "female" "male"   "female" "male"  
 [127] "male"   "female" "female" "male"   "male"   "male"   "female"
 [134] "female" "female" "male"   "male"   "male"   "male"   "female"
 [141] "male"   "male"   "female" "male"   "male"   "male"   "male"  
 [148] "female" "female" "male"   "male"   "male"   "male"   "female"
 [155] "female" "female" "female" "female" "female" "female" "male"  
 [162] "female" "male"   "male"   "male"   "male"   "male"   "female"
 [169] "female" "female" "male"   "male"   "male"   "male"   "female"
 [176] "male"   "female" "male"   "male"   "male"   "female" "female"
 [183] "female" "female" "female" "male"   "female" "male"   "female"
 [190] "male"   "female" "female" "male"   "female" "male"   "male"  
 [197] "male"   "male"   "female" "female" "male"   "male"   "female"
 [204] "male"   "female" "male"   "male"   "female" "male"   "female"
 [211] "male"   "male"   "male"   "male"   "male"   "female" "male"  
 [218] "female" "female" "male"   "female" "female" "male"   "male"  
 [225] "female" "female" "female" "female" "male"   "female" "male"  
 [232] "female" "male"   "male"   "male"   "male"   "female" "female"
 [239] "female" "male"   "female" "female" "female" "female" "female"
 [246] "female" "male"   "male"   "female" "male"   "female" "male"  
 [253] "female" "female" "male"   "female" "female" "male"   "male"  
 [260] "female" "female" "male"   "male"   "male"   "female" "female"
 [267] "male"   "female" "female" "male"   "female" "male"   "female"
 [274] "male"   "male"   "male"   "male"   "male"   "female" "female"
 [281] "male"   "male"   "male"   "male"   "female" "male"   "male"  
 [288] "male"   "female" "female" "female" "female" "male"   "female"
 [295] "male"   "female" "female" "male"   "male"   "female" "male"  
 [302] "male"   "male"   "male"   "male"   "female" "female" "female"
 [309] "male"   "female" "female" "male"   "male"   "male"   "male"  
 [316] "female" "male"   "male"   "female" "male"   "female" "male"  
 [323] "female" "male"   "female" "female" "female" "male"   "female"
 [330] "female" "female" "male"   "male"   "male"   "female" "female"
 [337] "male"   "female" "male"   "female" "male"   "female" "male"  
 [344] "male"   "male"   "female" "male"   "male"   "male"   "female"
 [351] "female" "male"   "female" "female" "female" "female" "male"  
 [358] "male"   "male"   "female" "male"   "female" "male"   "female"
 [365] "male"   "female" "male"   "male"   "female" "female" "female"
 [372] "female" "male"   "female" "male"   "female" "male"   "female"
 [379] "female" "male"   "male"   "female" "female" "male"   "female"
 [386] "female" "female" "male"   "female" "male"   "male"   "female"
 [393] "female" "male"   "female" "female" "female" "male"   "female"
 [400] "male"   "female" "female" "female" "female" "female" "female"
 [407] "female" "male"   "male"   "female" "female" "male"   "male"  
 [414] "male"   "male"   "female" "male"   "male"   "male"   "male"  
 [421] "male"   "male"   "male"   "female" "male"   "female" "female"
 [428] "female" "male"   "female" "male"   "female" "female" "male"  
 [435] "male"   "female" "female" "female" "male"   "male"   "female"
 [442] "female" "male"   "female" "male"   "female" "male"   "male"  
 [449] "male"   "female" "male"   "female" "male"   "male"   "female"
 [456] "male"   "male"   "female" "male"   "female" "female" "male"  
 [463] "female" "female" "female" "female" "female" "male"   "female"
 [470] "male"   "male"   "female" "male"   "male"   "female" "female"
 [477] "male"   "female" "female" "female" "female" "male"   "female"
 [484] "male"   "male"   "male"   "female" "male"   "male"   "male"  
 [491] "male"   "female" "male"   "male"   "female" "male"   "female"
 [498] "male"   "male"   "male"   "female" "female" "female" "male"  
 [505] "female" "female" "male"   "male"   "male"   "female" "female"
 [512] "female" "male"   "female" "male"   "female" "male"   "female"
 [519] "female" "female" "male"   "male"   "male"   "male"   "female"
 [526] "male"   "male"   "male"   "female" "female" "male"   "male"  
 [533] "male"   "male"   "female" "female" "male"   "male"   "male"  
 [540] "female" "female" "male"   "female" "male"   "female" "male"  
 [547] "male"   "male"   "female" "female" "female" "male"   "male"  
 [554] "male"   "male"   "female" "female" "male"   "female" "female"
 [561] "male"   "female" "female" "male"   "male"   "female" "female"
 [568] "male"   "male"   "male"   "female" "female" "male"   "female"
 [575] "male"   "male"   "male"   "female" "male"   "male"   "male"  
 [582] "male"   "female" "female" "male"   "male"   "male"   "female"
 [589] "female" "male"   "male"   "female" "male"   "female" "female"
 [596] "male"   "male"   "male"   "female" "male"   "male"   "female"
 [603] "male"   "male"   "female" "female" "male"   "female" "male"  
 [610] "male"   "male"   "male"   "female" "female" "female" "male"  
 [617] "female" "male"   "female" "male"   "male"   "female" "male"  
 [624] "male"   "male"   "female" "female" "male"   "male"   "female"
 [631] "male"   "female" "female" "female" "female" "female" "male"  
 [638] "male"   "female" "male"   "male"   "female" "male"   "female"
 [645] "female" "male"   "male"   "female" "female" "male"   "female"
 [652] "female" "male"   "male"   "male"   "female" "female" "female"
 [659] "female" "female" "male"   "female" "male"   "male"   "male"  
 [666] "female" "male"   "female" "male"   "male"   "female" "female"
 [673] "male"   "female" "male"   "male"   "female" "female" "female"
 [680] "male"   "female" "male"   "female" "female" "male"   "female"
 [687] "female" "female" "female" "female" "male"   "female" "male"  
 [694] "male"   "male"   "female" "male"   "female" "female" "male"  
 [701] "female" "female" "male"   "female" "male"   "female" "male"  
 [708] "female" "male"   "female" "female" "female" "male"   "male"  
 [715] "female" "female" "male"   "female" "male"   "male"   "male"  
 [722] "male"   "female" "female" "male"   "female" "male"   "male"  
 [729] "male"   "female" "female" "female" "female" "male"   "male"  
 [736] "male"   "male"   "male"   "male"   "female" "female" "female"
 [743] "female" "female" "female" "female" "female" "female" "male"  
 [750] "female" "male"   "male"   "male"   "male"   "female" "female"
 [757] "female" "male"   "female" "female" "female" "female" "male"  
 [764] "female" "male"   "male"   "male"   "female" "female" "male"  
 [771] "female" "female" "male"   "male"   "female" "male"   "male"  
 [778] "male"   "female" "female" "female" "female" "female" "female"
 [785] "female" "female" "male"   "female" "female" "female" "male"  
 [792] "male"   "female" "male"   "male"   "female" "male"   "male"  
 [799] "female" "female" "male"   "female" "male"   "male"   "female"
 [806] "male"   "female" "male"   "female" "female" "female" "female"
 [813] "female" "female" "male"   "male"   "male"   "male"   "female"
 [820] "male"   "male"   "female" "female" "male"   "male"   "female"
 [827] "male"   "male"   "female" "male"   "female" "male"   "male"  
 [834] "female" "male"   "female" "female" "male"   "male"   "male"  
 [841] "female" "male"   "female" "female" "female" "female" "male"  
 [848] "male"   "male"   "female" "male"   "male"   "male"   "male"  
 [855] "male"   "female" "female" "male"   "female" "male"   "male"  
 [862] "female" "male"   "male"   "female" "male"   "male"   "female"
 [869] "male"   "male"   "female" "female" "female" "male"   "male"  
 [876] "male"   "female" "male"   "female" "female" "male"   "female"
 [883] "female" "male"   "male"   "female" "male"   "male"   "male"  
 [890] "male"   "female" "female" "female" "male"   "female" "female"
 [897] "male"   "male"   "female" "female" "female" "male"   "female"
 [904] "male"   "male"   "male"   "female" "male"   "male"   "female"
 [911] "female" "female" "male"   "female" "male"   "male"   "male"  
 [918] "female" "male"   "male"   "male"   "male"   "male"   "male"  
 [925] "male"   "female" "female" "male"   "male"   "female" "male"  
 [932] "male"   "male"   "male"   "female" "male"   "female" "male"  
 [939] "female" "male"   "male"   "female" "male"   "female" "male"  
 [946] "female" "female" "male"   "female" "male"   "female" "female"
 [953] "male"   "female" "female" "male"   "female" "male"   "female"
 [960] "male"   "female" "male"   "female" "female" "male"   "male"  
 [967] "female" "female" "male"   "female" "male"   "female" "male"  
 [974] "female" "female" "female" "male"   "female" "female" "male"  
 [981] "male"   "female" "female" "male"   "female" "male"   "male"  
 [988] "female" "male"   "female" "male"   "male"   "female" "female"
 [995] "male"   "male"   "female" "female" "male"   "male"   "male"  
[1002] "male"   "male"   "male"   "male"   "male"   "male"   "female"
[1009] "female" "female" "female" "male"   "female" "male"   "female"
[1016] "male"   "male"   "female" "male"   "female" "male"   "male"  
[1023] "male"   "female" "female" "male"   "male"   "male"   "female"
[1030] "female" "male"   "female" "male"   "female" "female" "male"  
[1037] "male"   "male"   "female" "female" "male"   "female" "male"  
[1044] "male"   "female" "male"   "male"   "male"   "female" "female"
[1051] "male"   "male"   "male"   "female" "female" "female" "female"
[1058] "female" "male"   "male"   "male"   "female" "male"   "female"
[1065] "female" "male"   "female" "female" "female" "male"   "female"
[1072] "female" "female" "male"   "female" "female" "male"   "female"
[1079] "male"   "male"   "male"   "male"   "male"   "male"   "male"  
[1086] "female" "female" "male"   "female" "male"   "male"   "female"
[1093] "male"   "female" "female" "male"   "female" "female" "female"
[1100] "female" "female" "female" "female" "male"   "male"   "female"
[1107] "male"   "male"   "female" "female" "male"   "female" "male"  
[1114] "male"   "female" "female" "male"   "male"   "male"   "female"
[1121] "female" "male"   "male"   "female" "female" "male"   "male"  
[1128] "female" "male"   "female" "male"   "male"   "male"   "female"
[1135] "female" "female" "male"   "male"   "female" "male"   "male"  
[1142] "male"   "female" "male"   "male"   "male"   "female" "female"
[1149] "male"   "female" "male"   "female" "male"   "female" "female"
[1156] "female" "male"   "male"   "male"   "female" "female" "male"  
[1163] "male"   "male"   "male"   "female" "female" "female" "female"
[1170] "male"   "female" "male"   "female" "female" "female" "female"
[1177] "male"   "male"   "male"   "female" "male"   "male"   "male"  
[1184] "female" "female" "female" "female" "male"   "female" "male"  
[1191] "female" "male"   "male"   "male"   "male"   "male"   "female"
[1198] "female" "female" "female" "male"   "male"   "male"   "female"
[1205] "male"   "female" "male"   "female" "male"   "male"   "male"  
[1212] "female" "male"   "male"   "female" "female" "female" "male"  
[1219] "female" "female" "female" "male"   "female" "male"   "female"
[1226] "male"   "female" "male"   "male"   "female" "male"   "male"  
[1233] "male"   "female" "male"   "female" "male"   "male"   "male"  
[1240] "female" "female" "female" "female" "male"   "male"   "female"
[1247] "female" "male"   "female" "female" "male"   "male"   "female"
[1254] "male"   "male"   "female" "male"   "female" "female" "male"  
[1261] "male"   "female" "male"   "female" "male"   "female" "male"  
[1268] "male"   "female" "male"   "female" "male"   "female" "female"
[1275] "male"   "male"   "female" "male"   "female" "male"   "male"  
[1282] "female" "male"   "female" "female" "female" "male"   "male"  
[1289] "male"   "female" "male"   "male"   "female" "female" "female"
[1296] "male"   "female" "male"   "male"   "female" "female" "female"
[1303] "female" "male"   "male"   "male"   "female" "male"   "male"  
[1310] "male"   "male"   "female" "female" "male"   "male"   "female"
[1317] "male"   "male"   "female" "female" "female" "male"   "female"
[1324] "female" "female" "female" "male"   "female" "male"   "male"  
[1331] "female" "female" "male"   "female" "male"   "male"   "female"
[1338] "female" "female" "male"   "female" "male"   "male"   "male"  
[1345] "female" "male"   "male"   "male"   "female" "female" "female"
[1352] "male"   "male"   "female" "male"   "male"   "male"   "male"  
[1359] "female" "male"   "male"   "female" "male"   "female" "male"  
[1366] "male"   "female" "female" "female" "male"   "male"   "male"  
[1373] "male"   "male"   "male"   "male"   "male"   "male"   "female"
[1380] "male"   "female" "male"   "female" "female" "female" "male"  
[1387] "female" "female" "male"   "male"   "female" "male"   "male"  
[1394] "female" "female" "male"   "male"   "female" "female" "female"
[1401] "male"   "female" "male"   "female" "female" "male"   "female"
[1408] "male"   "female" "female" "male"   "male"   "female" "male"  
[1415] "male"   "male"   "female" "male"   "female" "female" "female"
[1422] "female" "male"   "female" "female" "male"   "female" "female"
[1429] "female" "male"   "male"   "male"   "female" "female" "male"  
[1436] "male"   "male"   "male"   "male"   "female" "male"   "female"
[1443] "female" "female" "female" "female" "female" "female" "male"  
[1450] "female"

Recode multiple categories with case_when()

The mother’s race is encoded as integers from 1 through 8:

NCbirths |>
  pull(RaceMom)
   [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 1 1 5 1 1 5 1 5 1 1 1 5 1 1 1 5 1
  [35] 1 1 5 5 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 5 1 5 1 1 5
  [69] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 5 1 1 1 1 1 1 1 1 1 1 1 5 1 1
 [103] 1 5 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 1 1 1 1 1 1 5 1 1 5 1 1 1 1 1 5 1
 [137] 1 1 1 1 1 1 5 1 1 5 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 5 5 1 1
 [171] 1 5 1 1 1 5 5 1 5 1 1 1 1 1 1 1 1 1 1 1 5 1 1 5 1 1 1 1 1 1 1 1 1 1
 [205] 1 1 1 5 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
 [239] 5 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 5 1 1 1 1 5 1 1 1 1
 [273] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
 [307] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 5 1 1 5 1 1 1 1 1 1 1 1
 [341] 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1
 [375] 1 1 5 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 5 1 1 1 1 5 1 5 1 1 1 5 1 1 1 1
 [409] 1 1 1 1 1 5 1 1 1 1 1 5 1 1 5 1 1 1 1 5 1 1 5 1 1 1 1 1 1 1 1 1 1 1
 [443] 1 1 1 5 1 5 1 1 1 1 1 1 1 1 1 1 5 1 1 5 1 1 1 5 1 1 1 1 5 1 1 5 1 1
 [477] 1 1 1 5 1 1 1 1 1 1 1 5 1 1 1 1 1 1 5 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1
 [511] 1 5 1 1 1 5 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1
 [545] 1 1 1 1 1 1 1 1 1 5 1 5 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1
 [579] 1 1 5 5 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 5 5 5 1 5 1
 [613] 1 1 5 5 1 5 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1
 [647] 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 5 1 5 5 1 5 1 1 1 1 1 1 1 1 5 1 1 1 1
 [681] 1 5 1 5 5 1 5 1 1 5 5 1 1 1 1 5 5 5 1 1 1 5 1 5 1 1 1 1 1 5 1 5 1 5
 [715] 1 1 1 5 1 1 1 1 1 1 1 1 5 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 5
 [749] 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 1 1 1 1 1 1 1 5 1 1 5 1 1 1 5 1 1
 [783] 1 1 1 1 5 1 5 1 5 1 1 1 1 1 1 1 1 1 5 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1
 [817] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 5 1 1
 [851] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1
 [885] 1 1 5 5 1 1 1 1 5 1 5 1 1 5 1 5 1 1 1 1 1 1 1 1 5 1 1 1 1 1 5 1 1 1
 [919] 1 1 1 5 1 1 1 5 1 1 5 1 1 1 1 1 1 1 1 1 5 1 1 1 1 5 1 1 5 5 1 5 1 1
 [953] 5 1 5 1 5 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 5 1 1 1 5 5 1
 [987] 1 5 1 1 1 1 1 1 1 1 1 1 1 5 1 5 1 1 1 1 5 5 5 1 1 1 1 1 1 1 1 1 1 1
[1021] 1 5 1 1 1 5 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5
[1055] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1089] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1123] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1157] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1191] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1225] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1259] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1293] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1327] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1361] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
[1395] 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 7 8
[1429] 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8

Recode multiple categories with case_when()

The mother’s race is encoded as integers from 1 through 8:

NCbirths |>
  pull(RaceMom) |>
  unique() # list all the unique values (ordered by first occurrence)
[1] 1 5 2 3 4 7 8

Recode multiple categories with case_when()

We use case_when() to recode multiple values all at once:

NCbirths |>
  mutate(
    RaceMom = case_when(
      RaceMom == 1 ~ "white",
      RaceMom == 2 ~ "black",
      RaceMom == 3 ~ "American Indian",
      RaceMom == 4 ~ "Chinese",
      RaceMom == 5 ~ "Japanese",
      RaceMom == 6 ~ "Hawaiian",
      RaceMom == 7 ~ "Filipino",
      RaceMom == 8 ~ 
        "Other Asian or Pacific Islander",
      TRUE ~ NA # should never reach
    )
  )

 

Recode multiple categories with case_when()

We use case_when() to recode multiple values all at once:

NCbirths |>
  mutate(
    RaceMom = case_when(
      RaceMom == 1 ~ "white",
      RaceMom == 2 ~ "black",
      RaceMom == 3 ~ "American Indian",
      RaceMom == 4 ~ "Chinese",
      RaceMom == 5 ~ "Japanese",
      RaceMom == 6 ~ "Hawaiian",
      RaceMom == 7 ~ "Filipino",
      RaceMom == 8 ~ 
        "Other Asian or Pacific Islander",
      TRUE ~ NA # should never reach
    )
  ) |>
  pull(RaceMom)
   [1] "white"                           "white"                          
   [3] "white"                           "white"                          
   [5] "white"                           "white"                          
   [7] "white"                           "white"                          
   [9] "white"                           "white"                          
  [11] "white"                           "white"                          
  [13] "white"                           "Japanese"                       
  [15] "white"                           "Japanese"                       
  [17] "white"                           "white"                          
  [19] "white"                           "Japanese"                       
  [21] "white"                           "white"                          
  [23] "Japanese"                        "white"                          
  [25] "Japanese"                        "white"                          
  [27] "white"                           "white"                          
  [29] "Japanese"                        "white"                          
  [31] "white"                           "white"                          
  [33] "Japanese"                        "white"                          
  [35] "white"                           "white"                          
  [37] "Japanese"                        "Japanese"                       
  [39] "Japanese"                        "white"                          
  [41] "white"                           "white"                          
  [43] "white"                           "white"                          
  [45] "white"                           "white"                          
  [47] "white"                           "white"                          
  [49] "white"                           "white"                          
  [51] "white"                           "white"                          
  [53] "white"                           "white"                          
  [55] "Japanese"                        "white"                          
  [57] "white"                           "white"                          
  [59] "white"                           "white"                          
  [61] "white"                           "white"                          
  [63] "Japanese"                        "white"                          
  [65] "Japanese"                        "white"                          
  [67] "white"                           "Japanese"                       
  [69] "white"                           "white"                          
  [71] "white"                           "white"                          
  [73] "white"                           "white"                          
  [75] "white"                           "white"                          
  [77] "white"                           "white"                          
  [79] "white"                           "white"                          
  [81] "white"                           "white"                          
  [83] "white"                           "Japanese"                       
  [85] "white"                           "Japanese"                       
  [87] "white"                           "Japanese"                       
  [89] "white"                           "white"                          
  [91] "white"                           "white"                          
  [93] "white"                           "white"                          
  [95] "white"                           "white"                          
  [97] "white"                           "white"                          
  [99] "white"                           "Japanese"                       
 [101] "white"                           "white"                          
 [103] "white"                           "Japanese"                       
 [105] "white"                           "white"                          
 [107] "white"                           "white"                          
 [109] "white"                           "white"                          
 [111] "white"                           "white"                          
 [113] "white"                           "white"                          
 [115] "white"                           "Japanese"                       
 [117] "white"                           "Japanese"                       
 [119] "white"                           "white"                          
 [121] "white"                           "white"                          
 [123] "white"                           "white"                          
 [125] "white"                           "Japanese"                       
 [127] "white"                           "white"                          
 [129] "Japanese"                        "white"                          
 [131] "white"                           "white"                          
 [133] "white"                           "white"                          
 [135] "Japanese"                        "white"                          
 [137] "white"                           "white"                          
 [139] "white"                           "white"                          
 [141] "white"                           "white"                          
 [143] "Japanese"                        "white"                          
 [145] "white"                           "Japanese"                       
 [147] "Japanese"                        "white"                          
 [149] "white"                           "white"                          
 [151] "white"                           "white"                          
 [153] "white"                           "white"                          
 [155] "white"                           "white"                          
 [157] "white"                           "white"                          
 [159] "white"                           "white"                          
 [161] "white"                           "white"                          
 [163] "Japanese"                        "white"                          
 [165] "Japanese"                        "white"                          
 [167] "Japanese"                        "Japanese"                       
 [169] "white"                           "white"                          
 [171] "white"                           "Japanese"                       
 [173] "white"                           "white"                          
 [175] "white"                           "Japanese"                       
 [177] "Japanese"                        "white"                          
 [179] "Japanese"                        "white"                          
 [181] "white"                           "white"                          
 [183] "white"                           "white"                          
 [185] "white"                           "white"                          
 [187] "white"                           "white"                          
 [189] "white"                           "white"                          
 [191] "Japanese"                        "white"                          
 [193] "white"                           "Japanese"                       
 [195] "white"                           "white"                          
 [197] "white"                           "white"                          
 [199] "white"                           "white"                          
 [201] "white"                           "white"                          
 [203] "white"                           "white"                          
 [205] "white"                           "white"                          
 [207] "white"                           "Japanese"                       
 [209] "white"                           "white"                          
 [211] "white"                           "white"                          
 [213] "white"                           "white"                          
 [215] "white"                           "white"                          
 [217] "white"                           "Japanese"                       
 [219] "white"                           "white"                          
 [221] "white"                           "white"                          
 [223] "white"                           "white"                          
 [225] "white"                           "white"                          
 [227] "white"                           "white"                          
 [229] "white"                           "white"                          
 [231] "white"                           "white"                          
 [233] "white"                           "white"                          
 [235] "white"                           "white"                          
 [237] "white"                           "white"                          
 [239] "Japanese"                        "white"                          
 [241] "white"                           "white"                          
 [243] "white"                           "white"                          
 [245] "Japanese"                        "white"                          
 [247] "white"                           "white"                          
 [249] "white"                           "white"                          
 [251] "white"                           "white"                          
 [253] "white"                           "white"                          
 [255] "white"                           "white"                          
 [257] "white"                           "white"                          
 [259] "white"                           "white"                          
 [261] "white"                           "Japanese"                       
 [263] "Japanese"                        "white"                          
 [265] "white"                           "white"                          
 [267] "white"                           "Japanese"                       
 [269] "white"                           "white"                          
 [271] "white"                           "white"                          
 [273] "white"                           "white"                          
 [275] "white"                           "white"                          
 [277] "white"                           "white"                          
 [279] "white"                           "white"                          
 [281] "white"                           "white"                          
 [283] "white"                           "white"                          
 [285] "white"                           "white"                          
 [287] "white"                           "white"                          
 [289] "white"                           "white"                          
 [291] "white"                           "white"                          
 [293] "white"                           "white"                          
 [295] "white"                           "white"                          
 [297] "white"                           "white"                          
 [299] "white"                           "white"                          
 [301] "white"                           "white"                          
 [303] "white"                           "white"                          
 [305] "white"                           "white"                          
 [307] "white"                           "white"                          
 [309] "white"                           "white"                          
 [311] "white"                           "white"                          
 [313] "white"                           "white"                          
 [315] "white"                           "white"                          
 [317] "white"                           "white"                          
 [319] "white"                           "white"                          
 [321] "white"                           "white"                          
 [323] "white"                           "Japanese"                       
 [325] "white"                           "white"                          
 [327] "white"                           "white"                          
 [329] "Japanese"                        "white"                          
 [331] "white"                           "Japanese"                       
 [333] "white"                           "white"                          
 [335] "white"                           "white"                          
 [337] "white"                           "white"                          
 [339] "white"                           "white"                          
 [341] "white"                           "white"                          
 [343] "white"                           "white"                          
 [345] "Japanese"                        "white"                          
 [347] "white"                           "white"                          
 [349] "white"                           "white"                          
 [351] "white"                           "white"                          
 [353] "white"                           "white"                          
 [355] "white"                           "white"                          
 [357] "white"                           "white"                          
 [359] "white"                           "white"                          
 [361] "white"                           "white"                          
 [363] "white"                           "white"                          
 [365] "white"                           "white"                          
 [367] "Japanese"                        "white"                          
 [369] "white"                           "white"                          
 [371] "white"                           "white"                          
 [373] "white"                           "white"                          
 [375] "white"                           "white"                          
 [377] "Japanese"                        "white"                          
 [379] "white"                           "white"                          
 [381] "white"                           "white"                          
 [383] "white"                           "white"                          
 [385] "white"                           "Japanese"                       
 [387] "white"                           "white"                          
 [389] "white"                           "white"                          
 [391] "white"                           "white"                          
 [393] "Japanese"                        "white"                          
 [395] "white"                           "white"                          
 [397] "white"                           "Japanese"                       
 [399] "white"                           "Japanese"                       
 [401] "white"                           "white"                          
 [403] "white"                           "Japanese"                       
 [405] "white"                           "white"                          
 [407] "white"                           "white"                          
 [409] "white"                           "white"                          
 [411] "white"                           "white"                          
 [413] "white"                           "Japanese"                       
 [415] "white"                           "white"                          
 [417] "white"                           "white"                          
 [419] "white"                           "Japanese"                       
 [421] "white"                           "white"                          
 [423] "Japanese"                        "white"                          
 [425] "white"                           "white"                          
 [427] "white"                           "Japanese"                       
 [429] "white"                           "white"                          
 [431] "Japanese"                        "white"                          
 [433] "white"                           "white"                          
 [435] "white"                           "white"                          
 [437] "white"                           "white"                          
 [439] "white"                           "white"                          
 [441] "white"                           "white"                          
 [443] "white"                           "white"                          
 [445] "white"                           "Japanese"                       
 [447] "white"                           "Japanese"                       
 [449] "white"                           "white"                          
 [451] "white"                           "white"                          
 [453] "white"                           "white"                          
 [455] "white"                           "white"                          
 [457] "white"                           "white"                          
 [459] "Japanese"                        "white"                          
 [461] "white"                           "Japanese"                       
 [463] "white"                           "white"                          
 [465] "white"                           "Japanese"                       
 [467] "white"                           "white"                          
 [469] "white"                           "white"                          
 [471] "Japanese"                        "white"                          
 [473] "white"                           "Japanese"                       
 [475] "white"                           "white"                          
 [477] "white"                           "white"                          
 [479] "white"                           "Japanese"                       
 [481] "white"                           "white"                          
 [483] "white"                           "white"                          
 [485] "white"                           "white"                          
 [487] "white"                           "Japanese"                       
 [489] "white"                           "white"                          
 [491] "white"                           "white"                          
 [493] "white"                           "white"                          
 [495] "Japanese"                        "white"                          
 [497] "white"                           "white"                          
 [499] "white"                           "Japanese"                       
 [501] "white"                           "white"                          
 [503] "white"                           "white"                          
 [505] "white"                           "white"                          
 [507] "white"                           "white"                          
 [509] "white"                           "white"                          
 [511] "white"                           "Japanese"                       
 [513] "white"                           "white"                          
 [515] "white"                           "Japanese"                       
 [517] "white"                           "white"                          
 [519] "white"                           "Japanese"                       
 [521] "white"                           "white"                          
 [523] "white"                           "white"                          
 [525] "white"                           "white"                          
 [527] "white"                           "white"                          
 [529] "white"                           "white"                          
 [531] "white"                           "white"                          
 [533] "white"                           "Japanese"                       
 [535] "white"                           "white"                          
 [537] "white"                           "white"                          
 [539] "white"                           "white"                          
 [541] "white"                           "white"                          
 [543] "white"                           "white"                          
 [545] "white"                           "white"                          
 [547] "white"                           "white"                          
 [549] "white"                           "white"                          
 [551] "white"                           "white"                          
 [553] "white"                           "Japanese"                       
 [555] "white"                           "Japanese"                       
 [557] "white"                           "white"                          
 [559] "white"                           "white"                          
 [561] "white"                           "white"                          
 [563] "white"                           "white"                          
 [565] "white"                           "white"                          
 [567] "Japanese"                        "white"                          
 [569] "white"                           "white"                          
 [571] "white"                           "white"                          
 [573] "white"                           "white"                          
 [575] "white"                           "white"                          
 [577] "white"                           "white"                          
 [579] "white"                           "white"                          
 [581] "Japanese"                        "Japanese"                       
 [583] "white"                           "white"                          
 [585] "white"                           "white"                          
 [587] "white"                           "Japanese"                       
 [589] "white"                           "white"                          
 [591] "white"                           "white"                          
 [593] "white"                           "white"                          
 [595] "white"                           "white"                          
 [597] "white"                           "white"                          
 [599] "white"                           "white"                          
 [601] "white"                           "white"                          
 [603] "white"                           "white"                          
 [605] "white"                           "Japanese"                       
 [607] "Japanese"                        "Japanese"                       
 [609] "Japanese"                        "white"                          
 [611] "Japanese"                        "white"                          
 [613] "white"                           "white"                          
 [615] "Japanese"                        "Japanese"                       
 [617] "white"                           "Japanese"                       
 [619] "white"                           "white"                          
 [621] "white"                           "white"                          
 [623] "white"                           "Japanese"                       
 [625] "white"                           "white"                          
 [627] "white"                           "white"                          
 [629] "white"                           "white"                          
 [631] "white"                           "white"                          
 [633] "white"                           "white"                          
 [635] "white"                           "white"                          
 [637] "white"                           "Japanese"                       
 [639] "white"                           "white"                          
 [641] "white"                           "white"                          
 [643] "white"                           "white"                          
 [645] "white"                           "white"                          
 [647] "white"                           "white"                          
 [649] "white"                           "white"                          
 [651] "white"                           "white"                          
 [653] "Japanese"                        "white"                          
 [655] "white"                           "white"                          
 [657] "white"                           "white"                          
 [659] "white"                           "white"                          
 [661] "white"                           "Japanese"                       
 [663] "white"                           "Japanese"                       
 [665] "Japanese"                        "white"                          
 [667] "Japanese"                        "white"                          
 [669] "white"                           "white"                          
 [671] "white"                           "white"                          
 [673] "white"                           "white"                          
 [675] "white"                           "Japanese"                       
 [677] "white"                           "white"                          
 [679] "white"                           "white"                          
 [681] "white"                           "Japanese"                       
 [683] "white"                           "Japanese"                       
 [685] "Japanese"                        "white"                          
 [687] "Japanese"                        "white"                          
 [689] "white"                           "Japanese"                       
 [691] "Japanese"                        "white"                          
 [693] "white"                           "white"                          
 [695] "white"                           "Japanese"                       
 [697] "Japanese"                        "Japanese"                       
 [699] "white"                           "white"                          
 [701] "white"                           "Japanese"                       
 [703] "white"                           "Japanese"                       
 [705] "white"                           "white"                          
 [707] "white"                           "white"                          
 [709] "white"                           "Japanese"                       
 [711] "white"                           "Japanese"                       
 [713] "white"                           "Japanese"                       
 [715] "white"                           "white"                          
 [717] "white"                           "Japanese"                       
 [719] "white"                           "white"                          
 [721] "white"                           "white"                          
 [723] "white"                           "white"                          
 [725] "white"                           "white"                          
 [727] "Japanese"                        "white"                          
 [729] "Japanese"                        "white"                          
 [731] "white"                           "white"                          
 [733] "white"                           "white"                          
 [735] "white"                           "white"                          
 [737] "white"                           "white"                          
 [739] "white"                           "white"                          
 [741] "white"                           "white"                          
 [743] "white"                           "white"                          
 [745] "white"                           "white"                          
 [747] "Japanese"                        "Japanese"                       
 [749] "white"                           "white"                          
 [751] "white"                           "white"                          
 [753] "white"                           "white"                          
 [755] "white"                           "white"                          
 [757] "white"                           "white"                          
 [759] "white"                           "white"                          
 [761] "white"                           "Japanese"                       
 [763] "white"                           "Japanese"                       
 [765] "white"                           "white"                          
 [767] "white"                           "white"                          
 [769] "white"                           "white"                          
 [771] "white"                           "white"                          
 [773] "Japanese"                        "white"                          
 [775] "white"                           "Japanese"                       
 [777] "white"                           "white"                          
 [779] "white"                           "Japanese"                       
 [781] "white"                           "white"                          
 [783] "white"                           "white"                          
 [785] "white"                           "white"                          
 [787] "Japanese"                        "white"                          
 [789] "Japanese"                        "white"                          
 [791] "Japanese"                        "white"                          
 [793] "white"                           "white"                          
 [795] "white"                           "white"                          
 [797] "white"                           "white"                          
 [799] "white"                           "white"                          
 [801] "Japanese"                        "Japanese"                       
 [803] "white"                           "white"                          
 [805] "white"                           "white"                          
 [807] "white"                           "white"                          
 [809] "white"                           "white"                          
 [811] "white"                           "white"                          
 [813] "white"                           "white"                          
 [815] "white"                           "white"                          
 [817] "white"                           "white"                          
 [819] "white"                           "white"                          
 [821] "white"                           "white"                          
 [823] "white"                           "white"                          
 [825] "white"                           "white"                          
 [827] "white"                           "white"                          
 [829] "white"                           "white"                          
 [831] "white"                           "white"                          
 [833] "white"                           "white"                          
 [835] "white"                           "white"                          
 [837] "white"                           "white"                          
 [839] "Japanese"                        "white"                          
 [841] "white"                           "white"                          
 [843] "white"                           "white"                          
 [845] "white"                           "white"                          
 [847] "white"                           "Japanese"                       
 [849] "white"                           "white"                          
 [851] "white"                           "white"                          
 [853] "white"                           "white"                          
 [855] "white"                           "white"                          
 [857] "white"                           "white"                          
 [859] "white"                           "white"                          
 [861] "white"                           "white"                          
 [863] "white"                           "white"                          
 [865] "white"                           "white"                          
 [867] "Japanese"                        "white"                          
 [869] "white"                           "white"                          
 [871] "white"                           "Japanese"                       
 [873] "white"                           "white"                          
 [875] "white"                           "white"                          
 [877] "white"                           "white"                          
 [879] "white"                           "white"                          
 [881] "white"                           "white"                          
 [883] "white"                           "white"                          
 [885] "white"                           "white"                          
 [887] "Japanese"                        "Japanese"                       
 [889] "white"                           "white"                          
 [891] "white"                           "white"                          
 [893] "Japanese"                        "white"                          
 [895] "Japanese"                        "white"                          
 [897] "white"                           "Japanese"                       
 [899] "white"                           "Japanese"                       
 [901] "white"                           "white"                          
 [903] "white"                           "white"                          
 [905] "white"                           "white"                          
 [907] "white"                           "white"                          
 [909] "Japanese"                        "white"                          
 [911] "white"                           "white"                          
 [913] "white"                           "white"                          
 [915] "Japanese"                        "white"                          
 [917] "white"                           "white"                          
 [919] "white"                           "white"                          
 [921] "white"                           "Japanese"                       
 [923] "white"                           "white"                          
 [925] "white"                           "Japanese"                       
 [927] "white"                           "white"                          
 [929] "Japanese"                        "white"                          
 [931] "white"                           "white"                          
 [933] "white"                           "white"                          
 [935] "white"                           "white"                          
 [937] "white"                           "white"                          
 [939] "Japanese"                        "white"                          
 [941] "white"                           "white"                          
 [943] "white"                           "Japanese"                       
 [945] "white"                           "white"                          
 [947] "Japanese"                        "Japanese"                       
 [949] "white"                           "Japanese"                       
 [951] "white"                           "white"                          
 [953] "Japanese"                        "white"                          
 [955] "Japanese"                        "white"                          
 [957] "Japanese"                        "Japanese"                       
 [959] "white"                           "white"                          
 [961] "white"                           "white"                          
 [963] "white"                           "white"                          
 [965] "white"                           "white"                          
 [967] "white"                           "white"                          
 [969] "white"                           "white"                          
 [971] "white"                           "white"                          
 [973] "white"                           "white"                          
 [975] "white"                           "white"                          
 [977] "white"                           "white"                          
 [979] "Japanese"                        "Japanese"                       
 [981] "white"                           "white"                          
 [983] "white"                           "Japanese"                       
 [985] "Japanese"                        "white"                          
 [987] "white"                           "Japanese"                       
 [989] "white"                           "white"                          
 [991] "white"                           "white"                          
 [993] "white"                           "white"                          
 [995] "white"                           "white"                          
 [997] "white"                           "white"                          
 [999] "white"                           "Japanese"                       
[1001] "white"                           "Japanese"                       
[1003] "white"                           "white"                          
[1005] "white"                           "white"                          
[1007] "Japanese"                        "Japanese"                       
[1009] "Japanese"                        "white"                          
[1011] "white"                           "white"                          
[1013] "white"                           "white"                          
[1015] "white"                           "white"                          
[1017] "white"                           "white"                          
[1019] "white"                           "white"                          
[1021] "white"                           "Japanese"                       
[1023] "white"                           "white"                          
[1025] "white"                           "Japanese"                       
[1027] "white"                           "white"                          
[1029] "white"                           "white"                          
[1031] "white"                           "white"                          
[1033] "white"                           "white"                          
[1035] "white"                           "white"                          
[1037] "Japanese"                        "white"                          
[1039] "white"                           "white"                          
[1041] "white"                           "white"                          
[1043] "white"                           "white"                          
[1045] "white"                           "white"                          
[1047] "white"                           "white"                          
[1049] "white"                           "white"                          
[1051] "white"                           "white"                          
[1053] "white"                           "Japanese"                       
[1055] "white"                           "white"                          
[1057] "white"                           "white"                          
[1059] "white"                           "white"                          
[1061] "white"                           "white"                          
[1063] "white"                           "white"                          
[1065] "white"                           "white"                          
[1067] "white"                           "white"                          
[1069] "white"                           "white"                          
[1071] "black"                           "black"                          
[1073] "black"                           "black"                          
[1075] "black"                           "black"                          
[1077] "black"                           "black"                          
[1079] "black"                           "black"                          
[1081] "black"                           "black"                          
[1083] "black"                           "black"                          
[1085] "black"                           "black"                          
[1087] "black"                           "black"                          
[1089] "black"                           "black"                          
[1091] "black"                           "black"                          
[1093] "black"                           "black"                          
[1095] "black"                           "black"                          
[1097] "black"                           "black"                          
[1099] "black"                           "black"                          
[1101] "black"                           "black"                          
[1103] "black"                           "black"                          
[1105] "black"                           "black"                          
[1107] "black"                           "black"                          
[1109] "black"                           "black"                          
[1111] "black"                           "black"                          
[1113] "black"                           "black"                          
[1115] "black"                           "black"                          
[1117] "black"                           "black"                          
[1119] "black"                           "black"                          
[1121] "black"                           "black"                          
[1123] "black"                           "black"                          
[1125] "black"                           "black"                          
[1127] "black"                           "black"                          
[1129] "black"                           "black"                          
[1131] "black"                           "black"                          
[1133] "black"                           "black"                          
[1135] "black"                           "black"                          
[1137] "black"                           "black"                          
[1139] "black"                           "black"                          
[1141] "black"                           "black"                          
[1143] "black"                           "black"                          
[1145] "black"                           "black"                          
[1147] "black"                           "black"                          
[1149] "black"                           "black"                          
[1151] "black"                           "black"                          
[1153] "black"                           "black"                          
[1155] "black"                           "black"                          
[1157] "black"                           "black"                          
[1159] "black"                           "black"                          
[1161] "black"                           "black"                          
[1163] "black"                           "black"                          
[1165] "black"                           "black"                          
[1167] "black"                           "black"                          
[1169] "black"                           "black"                          
[1171] "black"                           "black"                          
[1173] "black"                           "black"                          
[1175] "black"                           "black"                          
[1177] "black"                           "black"                          
[1179] "black"                           "black"                          
[1181] "black"                           "black"                          
[1183] "black"                           "black"                          
[1185] "black"                           "black"                          
[1187] "black"                           "black"                          
[1189] "black"                           "black"                          
[1191] "black"                           "black"                          
[1193] "black"                           "black"                          
[1195] "black"                           "black"                          
[1197] "black"                           "black"                          
[1199] "black"                           "black"                          
[1201] "black"                           "black"                          
[1203] "black"                           "black"                          
[1205] "black"                           "black"                          
[1207] "black"                           "black"                          
[1209] "black"                           "black"                          
[1211] "black"                           "black"                          
[1213] "black"                           "black"                          
[1215] "black"                           "black"                          
[1217] "black"                           "black"                          
[1219] "black"                           "black"                          
[1221] "black"                           "black"                          
[1223] "black"                           "black"                          
[1225] "black"                           "black"                          
[1227] "black"                           "black"                          
[1229] "black"                           "black"                          
[1231] "black"                           "black"                          
[1233] "black"                           "black"                          
[1235] "black"                           "black"                          
[1237] "black"                           "black"                          
[1239] "black"                           "black"                          
[1241] "black"                           "black"                          
[1243] "black"                           "black"                          
[1245] "black"                           "black"                          
[1247] "black"                           "black"                          
[1249] "black"                           "black"                          
[1251] "black"                           "black"                          
[1253] "black"                           "black"                          
[1255] "black"                           "black"                          
[1257] "black"                           "black"                          
[1259] "black"                           "black"                          
[1261] "black"                           "black"                          
[1263] "black"                           "black"                          
[1265] "black"                           "black"                          
[1267] "black"                           "black"                          
[1269] "black"                           "black"                          
[1271] "black"                           "black"                          
[1273] "black"                           "black"                          
[1275] "black"                           "black"                          
[1277] "black"                           "black"                          
[1279] "black"                           "black"                          
[1281] "black"                           "black"                          
[1283] "black"                           "black"                          
[1285] "black"                           "black"                          
[1287] "black"                           "black"                          
[1289] "black"                           "black"                          
[1291] "black"                           "black"                          
[1293] "black"                           "black"                          
[1295] "black"                           "black"                          
[1297] "black"                           "black"                          
[1299] "black"                           "black"                          
[1301] "black"                           "black"                          
[1303] "black"                           "black"                          
[1305] "black"                           "black"                          
[1307] "black"                           "black"                          
[1309] "black"                           "black"                          
[1311] "black"                           "black"                          
[1313] "black"                           "black"                          
[1315] "black"                           "black"                          
[1317] "black"                           "black"                          
[1319] "black"                           "black"                          
[1321] "black"                           "black"                          
[1323] "black"                           "black"                          
[1325] "black"                           "black"                          
[1327] "black"                           "black"                          
[1329] "black"                           "black"                          
[1331] "black"                           "black"                          
[1333] "black"                           "black"                          
[1335] "black"                           "black"                          
[1337] "black"                           "black"                          
[1339] "black"                           "black"                          
[1341] "black"                           "black"                          
[1343] "black"                           "black"                          
[1345] "black"                           "black"                          
[1347] "black"                           "black"                          
[1349] "black"                           "black"                          
[1351] "black"                           "black"                          
[1353] "black"                           "black"                          
[1355] "black"                           "black"                          
[1357] "black"                           "black"                          
[1359] "black"                           "black"                          
[1361] "black"                           "black"                          
[1363] "black"                           "black"                          
[1365] "black"                           "black"                          
[1367] "black"                           "black"                          
[1369] "black"                           "black"                          
[1371] "black"                           "black"                          
[1373] "black"                           "black"                          
[1375] "black"                           "black"                          
[1377] "black"                           "black"                          
[1379] "black"                           "black"                          
[1381] "black"                           "black"                          
[1383] "black"                           "black"                          
[1385] "black"                           "black"                          
[1387] "black"                           "black"                          
[1389] "black"                           "black"                          
[1391] "black"                           "black"                          
[1393] "black"                           "black"                          
[1395] "black"                           "black"                          
[1397] "black"                           "black"                          
[1399] "black"                           "black"                          
[1401] "black"                           "black"                          
[1403] "American Indian"                 "American Indian"                
[1405] "American Indian"                 "American Indian"                
[1407] "American Indian"                 "American Indian"                
[1409] "American Indian"                 "American Indian"                
[1411] "American Indian"                 "American Indian"                
[1413] "American Indian"                 "American Indian"                
[1415] "American Indian"                 "American Indian"                
[1417] "American Indian"                 "American Indian"                
[1419] "American Indian"                 "American Indian"                
[1421] "American Indian"                 "American Indian"                
[1423] "American Indian"                 "American Indian"                
[1425] "Chinese"                         "Chinese"                        
[1427] "Filipino"                        "Other Asian or Pacific Islander"
[1429] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1431] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1433] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1435] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1437] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1439] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1441] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1443] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1445] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1447] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"
[1449] "Other Asian or Pacific Islander" "Other Asian or Pacific Islander"

Make pairwise scatter plots

ggplot(NCbirths, aes(Plural, Sex, color = Sex)) + geom_point(position = "jitter", size = .5)
ggplot(NCbirths, aes(Plural, MomAge, color = Sex)) + geom_point(position = "jitter", size = .5)

 

Make pairwise scatter plots

ggplot(NCbirths, aes(Weeks, Plural, color = Sex)) + geom_point(position = "jitter", size = .5)
ggplot(NCbirths, aes(Weeks, Gained, color = Sex)) + geom_point(position = "jitter", size = .5)

 

If possible, make scatter plots of every variable against every other variable

Working with missing values in R

R propagates missingness

x <- c(1, 2, NA, 4)

sum(x)
[1] NA
mean(x)
[1] NA
x == 2
[1] FALSE  TRUE    NA FALSE

Many functions allow explicit exclusion of NA values

x <- c(1, 2, NA, 4)

sum(x, na.rm = TRUE)
[1] 7
mean(x, na.rm = TRUE)
[1] 2.333333

But is this the right thing to do?

There is no general right or wrong approach

x <- c(2, 1, 1, 2, 1, 1, 1, 2, NA, 1, 2, 1, 1, 2, 1, 1, 1, 2)
mean(x, na.rm = TRUE)
[1] 1.352941
x <- c(NA, NA, NA, 2, NA, NA, NA, NA, NA, 1, NA, NA, NA, NA)
mean(x, na.rm = TRUE)
[1] 1.5

R’s default is conservative: If there’s at least one NA, the result is NA

We need to use is.na() to check for missing values

c(1, 2, NA, 4) == NA   # does not work
[1] NA NA NA NA
is.na(c(1, 2, NA, 4))  # works
[1] FALSE FALSE  TRUE FALSE

Replacing NA values with something else

Remember from class on data wrangling:

band_data <- full_join(band_members, band_instruments)
band_data
# A tibble: 4 × 3
  name  band    plays 
  <chr> <chr>   <chr> 
1 Mick  Stones  <NA>  
2 John  Beatles guitar
3 Paul  Beatles bass  
4 Keith <NA>    guitar

Replacing NA values with something else

Replace NAs with empty strings in plays column:

band_data |>
  mutate(plays = replace_na(plays, ""))
# A tibble: 4 × 3
  name  band    plays   
  <chr> <chr>   <chr>   
1 Mick  Stones  ""      
2 John  Beatles "guitar"
3 Paul  Beatles "bass"  
4 Keith <NA>    "guitar"

Replacing NA values with something else

Replace NAs with empty strings in all columns:

band_data |>
  mutate(across(everything(), ~replace_na(.x, "")))
# A tibble: 4 × 3
  name  band      plays   
  <chr> <chr>     <chr>   
1 Mick  "Stones"  ""      
2 John  "Beatles" "guitar"
3 Paul  "Beatles" "bass"  
4 Keith ""        "guitar"

Replacing things with NA values

Replace empty strings with NA in plays column (requires naniar package):

band_data |>
  mutate(across(everything(), ~replace_na(.x, ""))) |>
  replace_with_na_at("plays", ~.x == "")
# A tibble: 4 × 3
  name  band      plays 
  <chr> <chr>     <chr> 
1 Mick  "Stones"  <NA>  
2 John  "Beatles" guitar
3 Paul  "Beatles" bass  
4 Keith ""        guitar

Replacing things with NA values

Replace empty strings with NA in all columns (requires naniar package):

band_data |>
  mutate(across(everything(), ~replace_na(.x, ""))) |>
  replace_with_na_all(~.x == "")
# A tibble: 4 × 3
  name  band    plays 
  <chr> <chr>   <chr> 
1 Mick  Stones  <NA>  
2 John  Beatles guitar
3 Paul  Beatles bass  
4 Keith <NA>    guitar

Removing rows with NA values

Remove all rows with any NAs with na.omit():

band_data |>
  na.omit()
# A tibble: 2 × 3
  name  band    plays 
  <chr> <chr>   <chr> 
1 John  Beatles guitar
2 Paul  Beatles bass  

Removing rows with NA values

Remove all rows where specific columns contain NAs:

band_data |>
  filter(!is.na(plays))
# A tibble: 3 × 3
  name  band    plays 
  <chr> <chr>   <chr> 
1 John  Beatles guitar
2 Paul  Beatles bass  
3 Keith <NA>    guitar

Removing rows with NA values

Conversely:

band_data |>
  filter(is.na(plays))
# A tibble: 1 × 3
  name  band   plays
  <chr> <chr>  <chr>
1 Mick  Stones <NA> 

Visualizing NAs

By default, missing points are not shown

ggplot(NCbirths) +
  aes(Weeks, Gained) +
  geom_point()

 

Visualizing NAs

Can show them with the naniar package

library(naniar)

ggplot(NCbirths) +
  aes(Weeks, Gained) +
  geom_miss_point()

 

Further reading