America has the largest per capita prison population in the world. When you combine the local jail, state and federal prison populations, there are approximately 2.3 million people currently behind bars and another 5 million or so under some form of correctional supervision. A lot of attention is focused on this demographic group and a lot of data is gathered about their background and circumstances while they are imprisoned. We know their age, sex, race and, of course, the crime that got them locked up. We know that men are incarcerated at a rate 14 times higher than women. We know that African Americans have an imprisonment rate seven times higher than whites; we know their recidivism chances upon release are high and their job prospects low, and so on. Yet, because of outmoded data collection strategies that fail to count the prison population in national data sets, beyond the tiny cocoon of prison, these people are largely invisible.

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