Monday, August 19, 2013

Crime down, prosecutions ... down?

On Friday, I published a chart showing that, despite dropping crime rates, the rate of people being sentenced in federal court has gone up.

As I mentioned then, one plausible explanation for this mismatch is that there is just something particular about federal crimes (which are a small slice of overall crimes). So I went looking for some state-only data. I was able to find some data on the number of number of felonies filed in Illinois courts each year since 1997. If you add that data, you get this chart:

(All three lines are normalized to an index rate of 100 in 1997, so this shows their relative change over time.)

The blue line is the new Illinois data. Unlike the federal sentencing rate (which has gone up despite the drop in crime) the Illinois felony-filing was steady between 1997 and 2006, after which it began to mirror the drop in the overall crime rate. So that's kind of encouraging. And it's evidence that undercuts my implicit hypothesis that the prosecution rate isn't at all sensitive to the crime rate.


  1. There are so many variables in trying to track the crime rate. Did you see Freakanomics on their theory that abortion causes a decrease in crime? It is hard to track all of the variables but I think you are hypothesis is probably right on wrong depending on a lot of factors, including the location of the study.

    1. I certainly agree that it's a complicated issue. Although I don't think there's much doubt that the crime rate has gone down -- the big controversy is why. That's where you get the theories like the Freakonmoics "roe v. wade" theory and the Kevin Drum lead-level theory (referenced in my previous post).

      I'm mainly interested in trying to figure out whether we can roll back some of our prosecutorial infrastructure now that there so much less crime than there used to be.

  2. Whether we should roll it back depends on whether or not you think it was at the appropriate level before the crime rate began to fall.

    I really do think that we don't celebrate the decrease in crime rate enough. Sometime big happened that really changed the quality of life and decreased a lot of human suffering and everyone just shrugs their shoulders.

    1. It also depends on how much credit you give the prosecutorial infrastructure for causing the drop in crime. There's a reasonable argument to made that policing tactics have contributed to the drop in crime. But with fewer crimes being actually committed, it seems like we could at least roll back prosecutions -- even if you think that policing tactics and more cops on the street are 100% responsible for the drop in crime (which no one actually thinks).


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