I wanted to see whether or not the death penalty really had a deterrent effect, because depending on whether I looked at an abolitionist or retentionist website, I found it to be either not deterrent or deterrent.
This file is the result of some research at the Bureau of Justice. I took their .csv files and made a chart. I'm looking for data for homicide rates before 1950 right now.
This program (in a zip file here) I wrote to evaluate whether or not some numbers I had really added up to what they claimed to. You can get the numbers from this site.