The authors maintain that incarceration rates are an important crime deterrent: by threatening potential criminals with years in jail, prisons influence people to commit fewer crimes. The authors ridicule criminologists for suggesting that incarceration rates
don't deter crime, accusing them of confusing causation and correlation. But it’s worth noting, for the sake of fairness, that there are many eminent criminologists who have argued that high incarceration rates don’t actually deter crime. One of the most persuasive arguments against high incarceration rates is that spending time in jail can push minor criminals into a life of serious crime—once they’re in “the system,” it’s hard to get out.