Friday, November 19, 2010
Ok this should be great, but on closer inspection it actually sucks.
My thoughts on first look: "Wow! I've still been going off this old homicides map because I haven't yet seen anything more precise. But block-by-block is amazing!"
But then I realized it's just a simple count of crimes for each block, not at all taking into account the size or population of the block. Hence universities, whose entire campuses count as one block, seem like the most dangerous places in the city. And then there's more obvious (and just dumb) examples like this pinwheel centered on Thomas Circle.
So yes, in reality it's not useless. I've seen some interesting things when comparing blocks of similar size. But it's pretty frustrating. Because the DC Crime Policy Institute it comes from gives no info that would help better interpret the data. And because the information they give us is already divided into bins (5-9 crimes/year, 10-25 crimes/year, etc) you can't manually correct for block size with any accuracy.
There's several easy steps they could've taken to produce a better (not perfect) representation of crime in The District. The easiest thing to do would be to simply divide the number of crimes by the area of the block. Then at least they wouldn't have made a map that was near-meaningless.
I guess since that would be so easy, the only conclusion I can come to is that the map was mostly decoration and what they were most interested in was the data in their table showing trends over time. But honestly I found that less interesting than the prospect of seeing the spatial distribution of crime in DC.
Posted at 6:15 PM