The study by the Crime & Justice Institute said the prospect of 20,000 inmates being released from prison each year, many without any supervision, is one of the consequences of the tough mandatory sentences that were enacted during the past decade to deal with gang and drug activity.

The report recommended eliminating most of the mandatory sentences, which account for about one-third of the inmate population today. It also recommended granting the Parole Board increased legal authority to supervise all offenders after incarceration.

Public Safety Secretary Ed Flynn characterized the needed changes as "moving from a sledgehammer approach to a scalpel approach" to avoid recidivism, in which roughly 40 percent of offenders return to prison within three years.

Lt. Gov. Kerry Healy said the Romney administration endorses many of the report's recommendations, but does not support eliminating mandatory sentences.

CJI Executive Director Elyse Clawson said one of the best ways to prevent recidivism is to monitor such things as substance abuse and anti-social behavior that drive criminal behavior.

She said the tight fiscal climate requires that post-incarceration supervision be based on need, with such people as sex offenders being heavily supervised while other offenders receive less oversight.