For the first time in decades, the nation may be on the verge of a wide-open debate on criminal justice policy. Lawmakers in both parties have introduced bills on sentencing reform. The Smarter Sentencing Act would decrease corrections costs by reducing mandatory minimum penalties for drug offenses. The Corrections Act would allow some prisoners to earn early release and reduce the likelihood of recidivism.

Unfortunately, perhaps no area of public policy is more warped by misconceptions than criminal justice. National and local policy is often made on the basis of anecdotes and rarely are hard data used to inform decision-making. Moreover, policies set decades ago, though outdated, are still in effect today.

Criminal justice reform should prioritize protecting public safety while reducing our world-high incarcerated population. Before the nation dives into a new debate about how to accomplish these goals, there are four key misconceptions that should be corrected.

1. Crime rates are not rising. Sensational news stories promote the impression that crime is on the rise. Mass shootings, for example, skew public perception of crime and danger. A 2011 Gallup poll found that 68 percent of Americans think crime is on the rise. They are wrong. Crime has been declining since the early 1990s. Violent crime has fallen by almost 50 percent since its peak in 1991. Last month, New York City saw its longest stretch without a single homicide since the early 1990s.

2. Penalties do not deter potential offenders. Deterrence philosophy — the idea that someone will choose not to commit a crime because of a specific penalty — is one justification often touted in support of harsh sentences, including three-strikes laws and the death penalty. However, all such punitive policies have proved unlikely to deter, because potential offenders typically underestimate the risks of getting caught and the possible punishments.