ArcGIS: Black White Incarceration Ratios

These maps indicate the ratio between the Black incarceration rate and the white incarceration rate, by state. Dark green indicates a ratio higher than 10:1 -- that is, the Black incarceration rate is ten times that of whites. The lightest blue indicates a ratio of 2:1 or less. Because we're looking at incarceration rates, these ratios factor in the relative population differences of each group.
Click on a state to see it's ratios, and the percent difference from 2009 to 2011.

2009 Ratios:

First observation: There was a far greater overall change between 2009 and 2011 than I had expected. The national ratio dropped from 6.5 : 1 to 4.6 : 1, which is an interesting area for further research. One hypothesis is that a combination of budget cuts and changes in policies may have lead to states releasing some lower level offenders, which may have been higher proportion African American (while convictions for more severe crimes may be somewhat more racially balanced).

Second observation: Generally the South, in both years, has relatively low ratios. Emphasis on 'relatively' -- because they're still incarcerating Blacks two to three times more than whites, relative to each population, but that ratio is far better than then nine to twenty times ratio in Minnesota. Here I hypothesize that given a larger Black population, rate of incarceration is lower, essentially merely because the denominator of that equation is lower.

Next steps:
Figuring out ArcGIS web app or story map to walk through the data.
Building in each state's Black population, see if that confirms my second hypothesis or if there are any other trends or anomalies there.
Bring in each state's overall incarceration rate, for reference.

Thank you to Professor Al Blumstein for the data and initial push on the project.