Monday, December 28, 2015

The Recidivism Rate Is Not What You Think It Is

I could have sworn I already posted about this, but I went looking for this topic on my blog and can't find it... so I guess not. Wow. This was one of the most shocking facts I learned in 2015, and I can't believe I haven't already talked about it.

One of the things we all "know is true" about prison is that the majority of inmates end up back inside pretty soon after they're released. The recidivism rate is actually only 50 to 55 percent within five years, so that's barely a majority. (The numbers are based on the 400,000 people released from state prisons in 2005 as reported by the Bureau of Justice Statistics.)

That 50 percent number may be lower than you thought already, but the research described in this incredible article from Slate shows that even 50 percent is misleadingly high. Yes, it's accurate for the 400,000 people released from prison that year, but that isn't what people think it means.

2 out of 3 people who serve time in prison never come back, and only 11 percent come back multiple times.

The reason for the shocking discrepancy between these new findings and those of the BJS, according to [Massachusetts–based public policy firm] Abt’s William Rhodes, is that the BJS used a sample population in which repeat offenders were vastly overrepresented.
What's wrong with the way the BJS does its sample?
It is difficult to explain to a nonstatistician. I try to use an analogy: Suppose that I were asked to describe a population of people who go to shopping malls. What I might do is go to the mall and perform an “intercept survey”—that is, I’d randomly select people who are entering the mall and ask them about themselves—record their age, sex, race, and frequency of visiting the mall. The problem is, I’d probably do that over a pretty short period of time, like a week. So I’d get a lot of people who are frequent mall visitors and fewer people who aren’t. You know, if you go to a mall you’ll see an elderly population who go daily, to exercise by walking through the mall. You’ll also see a number of people who simply like malls, and maybe they go weekly. Or you’ll find, occasionally, people like me, who go about once a year when they need to buy a washing machine or something. If you did a simple tabulation of all the people you intercepted during a week you’d get a large proportion of frequent mall visitors. And they wouldn’t be representative of people who visit malls—they’d be representative of frequent mall visitors....

[The BJS is] not attempting to be misleading. What they’re reporting is true: If you take people who are released from prison during a given year, here’s the rate at which they’ll return. But it gets translated in people’s heads as, “Here’s what happens to offenders in general.”

In truth what you have is two groups of offenders: those who repeatedly do crimes and accumulate in prisons because they get recaptured, reconvicted, and resentenced; and those who are much lower risk, and most of them will go to prison once and not come back. [emphasis added]
Acknowledging this reality has policy implications:
...there are very low-level offenders who manage to readjust, and you ought to focus the rehabilitation resources you have on those individuals who are high-risk offenders. They’re the ones who are going to benefit most from treatment—or, I should say, society’s going to benefit most from treating them. The problem, of course, is identifying them. That’s why criminologists have attempted to develop risk assessment tools, to identify the high-risk offenders and treat them, while almost letting the others recover by themselves.

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