Racial Disparities in Arrests - 2018 Q1

I’m continuing to look at arrests data in Charleston, SC. This time I’m looking at the arrests from January - March, 2018 for differences in arrest rates by race.

Population data is from the ACS 2016¹. Arrests data is from ²

To show the distribution of population and arrests, I’m using waffle charts. This is a 10x10 grid where each square represents 1%. Each row is 10% and each column is 10% so it’s a quick way to get a visual breakdown of the percentages in each category.

The racial make up of Charleston ³ has about 28% black, 69% white and x % other.

What stands out is there are more arrests by black males than any other category, and yet black males make up less than 30% of the population.

Looking at arrest types by race, blacks have more drug and distribution of drug arrests than whites, while whites have more alcohol related arrests.

For both blacks and whites, the most common type of drug arrest is simple possession of marijuana. The drug arrests have been divided into simple drug charges involving possession (Drug) and those that are related to distribution of drugs (Dist-Drug)

Here’s the percentage of each arrest type by race. Blacks account for 50% or more of arrests for Warrants, Drugs, Distribution of Drugs, Robbery and Gun related arrests. Whites account for more than 50% of arrests related to Alcohol, Traffic, Conduct, and Assault. Domestic Violence occurs almost equally for both blacks and whites.

Drilling down into the types of arrests, blacks have more drug arrests than whites, and whites and more alcohol arrests. Caveat Raw arrest data was free text form. I converted this to categories. The mapping from arrest type to arrest category is imperfect.

Look at how arrests occur by age and race. One difference is that arrests for alcohol related arrests are distributed differently between males and females. Blacks arrested for alcohol related offenses tend to be older, whereas for whites the arrests occur at a younger age.

There are clearly differences in who gets arrests, depending on race. There are different rates of arrests by race, and different types of arrests occur based on race.

Next I will look at what is causing these differences. Are the differences based on income or education? Is there a bias involved? Further investigation is need.