New Jersey is ninth on the list of states with a high release of unsupervised ex-cons. The states with the lowest percentages are Oregon and California - both below 1 percent.
Across the country, the average of unsupervised ex-inmates is 21 percent, about the same as in Pennsylvania, the report said, analyzing 2012 data.
"There's a broad consensus that public safety is best served when offenders have a period of supervision and services when they leave prison," Gelb said. "Yet the trend is toward releasing more and more inmates without any supervision or services whatsoever."
New Jersey Department of Corrections spokeswoman Deirdre Fedkenheuer said the department's commissioner received the report Wednesday afternoon and was reviewing it.
The Pew report recommends that policies require postprison supervision, permit discretionary parole decisions, apply conditions of release appropriate to offenders' risks and needs, and reinvest incarceration savings in supervision.
"This is where policymakers have a really strong opportunity to cut costs," Gelb said, "and cut crime at the same time."
The report gives a historical perspective of criminal-justice trends through the 1980s and '90s, when legislators across the country passed laws for mandatory sentences, removed discretionary parole releases, and built more prisons to keep more felons jailed.
New Jersey was among the first states in the late 1980s to pass mandatory sentences for those who sold drugs within 1,000 feet of a school. Prison populations swelled, with nonviolent offenders at times serving longer sentences than violent offenders.
Gelb said it made no sense to keep offenders jailed and supervised around the clock, then set them free without any information about where they are going, and no support services to find employment or stay sober.
The report cited a previous study from New Jersey that showed that paroled inmates with supervision were 36 percent less likely to return to prison than inmates who served longer sentences with no supervision.
According to a 2012 Pew survey, more than 65 percent of those polled preferred shorter sentences followed by supervision, especially for nonviolent offenders.
"The prevailing philosophy used to be that we just turn inmates loose at the prison gate with nothing more than a bus ticket and the clothes on their back," Gelb said. "Now, policymakers on both sides of the aisle are starting to realize that if you're serious about public safety, you need more effective strategies."
According to Pew's report, between 1990 and 2012, the number of inmates nationally who were released without supervision because they had served their maximum sentences grew 119 percent, from fewer than 50,000 to more than 100,000.
Nonviolent offenders are driving the increase, the report said, noting that 20 percent of drug offenders and 25 percent of property offenders were released without supervision in 2000, but those figures grew to 31 percent and 32 percent in 2011.
Marc Levin, policy director for Right on Crime, a conservative organization based in Texas, said the Pew report was on target and consistent with changes in his state, where fewer than 13 percent of prisoners are released without supervision.
On Wednesday, Levin was in Philadelphia for a conference on juvenile justice. Overhauling current laws, as the Pew report recommends, is a bipartisan effort, he said. "It's definitely important public policy," he said of the supervision. "It's holding people accountable, and it makes sense."