Home Owners’ Loan Corporation (HOLC) Grades and their Relationship to Racial Demographics

Appendix to report

Data cleaning

Setup

Loaded the packages we need for collecting and cleaning the data.

library(tidyverse)
library(readr)
library(skimr)
library(scales)

Cleaning the Data

Below we imported the raw data into a new data frame where we used separate() to make a column made up of city, state into two new columns containing the city and state respectively. We originally wanted to find the relationship between different regions of the United States and the percentage of their population that live within certain HOLC grades, and we cleaned the data in order to achieve this. However, we decided that we wanted to focus more on the relationship between HOLC grades and race, and ended up not using the region column that we made within our dataset.

metro_grades <- read_csv("data/metro-grades.csv") |>
  separate(
    col = metro_area,
    into = c("metro_area_city", "metro_area_state"),
    sep = "\\,"
  )

Rows: 551 Columns: 28
── Column specification ────────────────────────────────────────────────────────
Delimiter: ","
chr  (2): metro_area, holc_grade
dbl (26): white_pop, black_pop, hisp_pop, asian_pop, other_pop, total_pop, p...

ℹ Use `spec()` to retrieve the full column specification for this data.
ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.

metro_grades <- metro_grades |>
  mutate(metro_area_region = case_when(
    str_detect(string = metro_area_state, 
               pattern = "ME|VT|NH|MA|CT|FI|NY|NJ|PA") ~ "Northeast",
    str_detect(string = metro_area_state,
               pattern = "ND|SD|NE|KS|MN|IA|MO|WI|IL|IN|MI|OH") ~ "Midwest",
    str_detect(string = metro_area_state,
               pattern = "DE|MD|VA|WV|NC|SC|GA|FL|KY|TN|AL|MS|AR|LA|OK|TX") ~ "South",
    str_detect(string = metro_area_state,
               pattern = "WA|OR|CA|MT|ID|WY|NV|UT|CO|AZ|NM|HI|AK") ~ "West"
    )) |>
  relocate(metro_area_region, .after = metro_area_state)

Summary Statistics of HOLC Grades by Race

Summary of HOLC Grade A:

metro_grades |>
  filter(holc_grade == "A") |>
  select(pct_white:pct_other) |>
  summary(metro_grades)

   pct_white       pct_black         pct_hisp        pct_asian     
 Min.   :11.29   Min.   : 0.310   Min.   : 1.540   Min.   : 0.310  
 1st Qu.:68.53   1st Qu.: 2.373   1st Qu.: 3.770   1st Qu.: 1.232  
 Median :77.54   Median : 5.105   Median : 5.380   Median : 1.920  
 Mean   :73.78   Mean   : 8.888   Mean   : 8.949   Mean   : 3.100  
 3rd Qu.:83.04   3rd Qu.:11.425   3rd Qu.:10.360   3rd Qu.: 3.902  
 Max.   :94.12   Max.   :65.930   Max.   :74.850   Max.   :17.700  
   pct_other     
 Min.   : 1.780  
 1st Qu.: 4.110  
 Median : 5.085  
 Mean   : 5.288  
 3rd Qu.: 6.138  
 Max.   :13.280  

Summary of HOLC Grade B:

metro_grades |>
  filter(holc_grade == "B") |>
  select(pct_white:pct_other) |>
  summary(metro_grades)

   pct_white       pct_black         pct_hisp        pct_asian     
 Min.   : 6.63   Min.   : 1.190   Min.   : 1.600   Min.   : 0.180  
 1st Qu.:50.03   1st Qu.: 6.638   1st Qu.: 4.840   1st Qu.: 1.062  
 Median :62.86   Median :12.390   Median : 7.825   Median : 2.100  
 Mean   :59.94   Mean   :16.613   Mean   :14.273   Mean   : 3.296  
 3rd Qu.:72.12   3rd Qu.:23.457   3rd Qu.:17.385   3rd Qu.: 4.325  
 Max.   :90.97   Max.   :76.270   Max.   :90.770   Max.   :31.390  
   pct_other     
 Min.   : 1.040  
 1st Qu.: 4.625  
 Median : 5.590  
 Mean   : 5.879  
 3rd Qu.: 6.990  
 Max.   :15.460  

Summary of HOLC Grade C:

metro_grades |>
  filter(holc_grade == "C") |>
  select(pct_white:pct_other) |>
  summary(metro_grades)

   pct_white       pct_black        pct_hisp       pct_asian     
 Min.   : 6.99   Min.   : 1.85   Min.   : 1.83   Min.   : 0.140  
 1st Qu.:33.69   1st Qu.: 8.70   1st Qu.: 6.33   1st Qu.: 0.950  
 Median :48.43   Median :19.96   Median :11.26   Median : 2.220  
 Mean   :48.65   Mean   :23.01   Mean   :18.89   Mean   : 3.427  
 3rd Qu.:63.34   3rd Qu.:31.32   3rd Qu.:27.13   3rd Qu.: 3.750  
 Max.   :87.65   Max.   :83.36   Max.   :88.33   Max.   :24.380  
   pct_other     
 Min.   : 1.190  
 1st Qu.: 4.680  
 Median : 5.790  
 Mean   : 6.025  
 3rd Qu.: 7.280  
 Max.   :15.220  

Summary of HOLC Grade D:

metro_grades |>
  filter(holc_grade == "D") |>
  select(pct_white:pct_other) |>
  summary(metro_grades)

   pct_white       pct_black        pct_hisp        pct_asian     
 Min.   : 3.77   Min.   : 1.21   Min.   : 1.100   Min.   : 0.090  
 1st Qu.:22.55   1st Qu.:11.90   1st Qu.: 5.965   1st Qu.: 0.635  
 Median :39.85   Median :28.44   Median :11.690   Median : 1.685  
 Mean   :39.39   Mean   :31.44   Mean   :20.077   Mean   : 3.104  
 3rd Qu.:53.08   3rd Qu.:43.30   3rd Qu.:28.152   3rd Qu.: 3.770  
 Max.   :86.17   Max.   :85.40   Max.   :93.900   Max.   :23.710  
   pct_other     
 Min.   : 0.880  
 1st Qu.: 4.395  
 Median : 5.605  
 Mean   : 5.981  
 3rd Qu.: 7.380  
 Max.   :17.730