Million dollar blocks and the cost of incarceration

Posted to Maps  |  Tags: ,  |  Nathan Yau

Incarceration costs a lot of money. We know this, sort of. But how much really? Million Dollar Blocks, by Daniel Cooper and Ryan Lugalia-Hollon, estimates the cost in Chicago, down to the block level.

The map is based on data obtained by the Chicago Justice Project from the Cook County Circuit Court. It represents all adult convictions between the years of 2005-2009. For each conviction, we have data for what the offense was, the length of the sentence, and the offender’s residential address.

We derive dollar amounts from sentence lengths. Our cost assumption is that, on average, the Illinois Department of Corrections spends approximately $22,000 per year for each inmate. Life sentences are calculated based on average life expectancy.

As you might expect, a bulk of arrests occur in concentrated areas, hence the name of the project. Darker red means higher estimated costs.

Spending numbers appear in the bottom right corner when you mouse over blocks, but the map could use a legend to get a better sense of scale. It’d be especially helpful when you switch between all offenses and just drug-related ones. When you switch from the latter (the default view), which is a subset of the former, over to all offenses, the map becomes less red. But the spending is actually more.

Anyways, I hope they work on this more. It’s a good concept, and naturally, I’m wondering what it’s like in other places.

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