Epistemic status: highly uncertain
As of 2013, 2,220,300 adults were incarcerated in US state and federal prisons and county jails.
The majority of these people –about 60% — are incarcerated for nonviolent offenses such as theft, drugs, or public order violations.
How bad is this, in terms of years of life lost? How much damage is due to being imprisoned? (ETA: of course, in this context, I am only looking at the harms of prisons, not the benefits due to the deterrent effect of prisons, or the harms of crime. This should not be read as a claim that prison has zero deterrent effect!)
One article attempts to quantify:
African American males can expect to spend 3.09 years lifetime in prison, on average, and Hispanic and Caucasian males will spend on average 1.06 and 0.50 years, respectively.
Comparing life expectancies of people who have and have not gone to prison, as if “prison” were a disability, they compute that white males lose 19,665 person-years of life to prison per 100,000, black males lose 139,507 person-years, and Hispanic males lose 45,766 person-years.
For comparison purposes, here is a table of person-years of life lost to the most common diseases in the US. Cancer, the top killer, only appears to cost 2882 person-years of life per 100,000. All causes together only cost 38,211 person-years of life per 100,000.
These numbers are really weird. They would place prison as being responsible for nearly half of all person-years of life lost. That would be an utterly shocking result. I’m skeptical.
(ETA: it turns out that the authors of this study were looking at a stock, not a flow, of person-years lost to prison, as Ben notes below. Do not use this study’s numbers to estimate the harms of prison, they don’t make a lot of sense.)
Epidemiologist Ernest Drucker, in his book A Plague of Prisons, tried to quantify the years of life lost to imprisonment for drug offenses in New York State. He estimated a total of 360,000 years of life in prison between 1973 and 2008. This isn’t a fair comparison to diseases, though, because a year living in prison is not as bad as being dead, and prison has harms outside the time actually spent in prison. If we were to count years in prison as “years of life lost”, however, then, given that there are roughly 19 million people in New York, drug offenses alone cost 55 person-years of life per 100,000, which is a more modest number.
A study of the dose-response effect of years of prison on mortality found that each additional year in prison (compared to being released on parole) produced a 2-year decline in life expectancy. For comparison purposes, smokers lose on average 11-12 years of life expectancy compared to nonsmokers. Getting a diagnosis of colon cancer means losing about 10 years of life expectancy, while getting a diagnosis of testicular cancer means losing 1.3 years of life expectancy.
If we combine these numbers, assume each year in prison is roughly equivalent to two years of life lost, then New York State’s drug incarceration is responsible for about 110 person-years of life per 100,000, which is about half the death rate due to HIV. This is a more believable number, though it would still make the list of the top 15 causes of death by years of life lost. But it’s only for drug incarceration, which is responsible for only about 1/5 of all incarceration.
If we look at the total number of people incarcerated in New York State, or 77,227, we get an estimated 810 person-years of life lost to prison in New York per 100,000 population, which is more than the national YLL of homicide. And if we extrapolate to the full 2,220,300 Americans incarcerated, assume 2 years of life lost per year in prison, we get a rate of person-years of life lost due to prison per 100,000 population of 1396, which would make “prison”, if it counted as a cause of death, the sixth worst public health problem in terms of person-years of life lost.
The deadliness of prison, depending on which numbers you use, seems to range from “truly implausibly bad” to “one of the most serious public health problems in America.”
The leading causes of death among former inmates are drug overdose, cardiovascular disease, homicide, and suicide; the highest elevated risks, at 10-12x the population expected rates, were drug overdose and homicide, especially at 0-2 weeks after release. Prison puts people in more danger than they were before.
Some suggested mechanisms for why prison is so dangerous include poor conditions such as overcrowding that expose prisoners to infectious disease; violence within prisons; poor medical care inside prisons; and increased risky behaviors, due to trauma or psychological harm or lack of material opportunities for ex-cons.
For US-centric and present-day-centric utilitarian calculations, prison looks really, really bad. Reducing the prison population seems potentially important on a level comparable to working on Big Problems like cancer, heart disease, diabetes, car accidents, etc.
If nobody were imprisoned for drug crimes, then (aside from any additional risks incurred from the resulting increased drug use) the drop in incarceration alone would save more American lives than eradicating HIV from the US today.