NEW YORK — The number of offenders on parole and probation across the United States has surged past 5 million, complicating the challenges for fiscally ailing states as they try to curb corrections costs without jeopardizing public safety, according to a new report.

The Pew Center on the States report, released today, says the number of people on probation or parole nearly doubled to more than 5 million between 1982 and 2007. Including jail and prison inmates, the total population of the U.S. corrections system now exceeds 7.3 million — one of every 31 U.S. adults, it said.

The report also noted huge discrepancies among the states in regard to the total corrections population — one of every 13 adults in Georgia and one of every 18 in Idaho at one end of the scale, one of every 88 in New Hampshire at the other extreme. The racial gap also was stark — one of every 11 black adults is under correctional supervision, one of every 27 Hispanic adults, one of every 45 white adults.

The report notes that construction of new prisons will be increasingly rare as most states grapple with budget crises. It said improved community-supervision strategies represent one of the most feasible ways for states to limit corrections spending and reduce recidivism.

"Every single one of them should be making smart investments in community corrections that will help them cut costs and improve outcomes," said Susan Urahn, managing director of the Center on the States.

At present, according to the report, prisons consume nearly 90 percent of state corrections spending, even though two-thirds of offenders under supervision are on parole or probation. Costs per year for a prison inmate average nearly $29,000, while average costs for managing parolees and probationers range from $1,250 to $2,750 a year.

Adam Gelb, director of Pew's Public Safety Performance Project, stressed that violent and incorrigible criminals need to be locked up, but contended that many prison inmates could be safely overseen in their communities at far lower cost.

"New community supervision strategies and technologies need to be strengthened and expanded, not scaled back," he said. "Cutting them may appear to save a few dollars, but it doesn't. It will fuel the cycle of more crime, more victims, more arrests, more prosecutions, and still more imprisonment."

Among the report's recommendations for strengthening community corrections:

— Base intervention programs on sound research about what works to reduce recidivism.

— Use advances in supervision technology such as electronic monitoring and rapid-result alcohol and drug tests.

— Create incentives for offenders and supervision agencies to succeed, and monitor their performance.

— Impose swift, certain sanctions for offenders who break the rules of their release.

The report cited a probation program in Hawaii as a positive example. Under that program, which offers extensive counseling and treatment, failure to comply with random drug tests, office visits and treatment requirements is met with immediate sanctions — typically a few days in jail. Participants have proven far less likely than others on probation to be arrested for new crimes and sent back to prison.

Arizona was praised for a law enacted last year that creates performance incentives for offenders and the county-based probation supervision system. For every month that an offender complies with the terms of supervision, the length of probation can be shortened by up to 20 days. Slip-ups result in a loss of the earned time.

Kansas has made headway in curbing its prison population by offering grants to community corrections programs that cut down on the high number of probation and parole rule-breakers being sent back to prison solely for such rule violations.

The Pew report says strong community supervision programs for low-risk offenders not only cost much less than incarceration but, when properly funded and managed, can cut recidivism by as much as 30 percent. That could be a huge boon to the states, which, according to the National Association of State Budget Officers, spent a record $51.7 billion on corrections last fiscal year — up 300 percent over two decades.

The five states with the highest rate of adults under correctional supervision were Georgia, Idaho, Texas, Massachusetts and Ohio. Those with lowest rates were New Hampshire, Maine, West Virginia, Utah and North Dakota.

Georgia, although only the ninth most populous state, had more people on probation in 2007 — 435,631 — than any other state, according to the report. The state Department of Corrections said the number might be inflated by double-counting of some offenders, but it has previously acknowledged that its probation population is the highest per capita in the country.

One consequence, according to the department, is that Georgia probation officers have had a caseload far higher than the national average.