Design Lab: Infographic on Gun Control and Violent Crime

After last month’s one-day course taught by Edward Tufte, I was inspired to try creating my own complex infographic. I decided to tackle a subject that comes up rather frequently in discussions with one particular family member: the relationship between gun control laws and violent crime.

The graphic above charts 4 variables: the violent crime rate in a given state in 2008 (x axis), the strictness of a state’s gun control laws as ranked by gun control advocacy group the Brady Campaign (y axis), a state’s poverty rate in 2008 (on a spectrum from green [low] to black [high]) and a state’s “diversity index” (the likelihood that two randomly selected people will be of a different ethnic group, as determined by the 2000 census; the larger the type, the more diverse the state). I had also thought about indicating both geographical proximity (by means of connecting lines, but these made the graphic nearly illegible) and population density (though I could think of no concise means of indicating that New Jersey’s population density is 1000 times that of Alaska).

Now, I am no statistician or criminologist and I’ll leave the conclusions to them, but it seems to me that this graphic does pretty well at one of the jobs of a complex infographic by, well, complicating the problem. The chart shows pretty clearly that strict gun control laws do not necessarily lead to a lower rate of violent crimes, but it also shows that fewer restrictions on gun ownership also do not lead to a lower violent crime rate — an armed society is not, as some gun rights advocates would argue, necessarily a polite society (as to the wisdom of basing social policy on the musings of a science fiction writer, well, that’s probably a subject for another infographic). Nor do the other variables represented indicate a singular cause of violent crime: some of the most diverse states are among the least violent, as are some of the least wealthy states. What the graph makes clear, I think, is that there is no simple answer to reducing violent crime.

So what do you think? How could this graphic be improved? How could I add more variables while keeping the image legible? I’d love to see some of my designer friends take a hack at this same problem and come up with a different way of looking at the data (which is available here, by the way).