This is the ninth in a series from Dana Goldstein of the Justice Lab at The Marshall Project, Top 10 (Not Entirely Crazy) Theories Explaining the Great Crime Decline:
The prison boom
Because of increased drug-related arrests and mandatory minimum sentences, the American incarceration rate has more than quadrupled since 1970. Long prison sentences were supposed to incapacitate career criminals. Yet because criminals “age out” of law breaking whether or not they are in jail, incarceration itself could not have been the only driver of the crime decline.
The scholarly consensus is that mass incarceration accounted for about 10 to 20 percent of the overall crime drop since 1992. “If you did a thought experiment, let’s add a million people to the prison system, and let’s suppose 1 percent of them are really serious habitual offenders who commit 50 crimes per year, that’s a reduction of half a million crimes,” Roman says. “Whether the destruction of communities associated with mass incarceration is worth it? That’s a completely different question.”
The Marshall Project