Per capita use of force by type in NJ counties

force_type_map.R

library(tidyverse)

# Get number of incidents of selected types of force by county
# devtools::install_github("tor-gu/njoaguof")
library(njoaguof)
force_type_by_county <- incident %>%
  right_join(incident_subject_force_type) %>%
  mutate(
    force_type =
      fct_collapse(
        force_type,
        other_level = "Other",
        "Chemical Spray" = c("Discharged Chemical at", "High Volume OC Spray"),
        "Conducted Energy Device" = "Used CED on",
        "Dog bite" = c("Canine bit (apprehension)", "Canine bit (spontaneous)"),
        "Firearm discharge"="Discharged Firearm at",
      )
  ) %>%
  filter(force_type != "Other") %>%
  filter(incident_date_1 < "2022-02-01") %>%
  mutate(force_type = fct_drop(force_type, "Other")) %>%
  select(form_id, county = incident_municipality_county, force_type) %>%
  group_by(county) %>% count(force_type, .drop = FALSE)

# Get New Jersey county population data from the US Census
library(tidycensus)
county_pop <- get_estimates(geography = "county", product = "population")  %>%
  separate(NAME, sep=", ", into=c("county", "state")) %>%
  filter(state=="New Jersey", variable=="POP") %>%
  mutate(county=str_remove(county, " County")) %>%
  select(county, population=value)

# Combine the use of force data with the census data
force_by_percap <- force_type_by_county %>% right_join(county_pop) %>%
  mutate(per100k=n*100000/population) %>%
  select(county, force_type, per100k)


# Get the  New Jersey county map and plot
library(tigris)
options(tigris_use_cache=TRUE)
county_map <- counties(state="New Jersey", class="sf")

library(tmap)
county_map %>%
  geo_join(force_by_percap, by_sp="NAME", by_df="county", how="inner") %>%
  tm_shape() +
  tm_polygons("per100k", title="Per 100k", style="cont") +
  tm_facets("force_type", free.scales = TRUE) +
  tm_layout(main.title="NJ police use of force per capita\nOct 2020-Jan 2022") +
  tm_credits("US Census\nNJ OAG")