With the report last week that the number of people imprisoned in this country has reached an all-time high, Pennsylvania is no exception.

The state's inmate population has grown 21 percent in the past seven years, and on May 31 stood at 45,505.

That's nearly 13 percent over capacity, and Department of Corrections officials don't see any change in sight.

"We're just so crowded," said press secretary Susan McNaughton. "Our population increase is being driven by parole violators coming back into the system and nonviolent offenders.

"We know we need to do something."

That's why the state has turned to what it calls its intermediate punishment program.

Just two years into it, corrections officials believe it could be their savior, in terms of money and precious cell space.

"Our very expensive cell space should be saved for the most violent offenders -- murderers and rapists," Ms. McNaughton said.

Estimates for when the intermediate punishment program is in full swing call for an average cost savings of $15,000 per participant.

The most recent report on the program, which started receiving inmates in May 2005, showed 270 participants.

In 2006, 1,933 offenders were eligible for intermediate punishment, and 234 entered the program.

There are four phases, and the program lasts 24 months. The first phase is confinement in a state correctional institution for at least seven months. During that time, the participant spends at least four months in an intensive inpatient drug and alcohol treatment program.

In phase two, the participant spends a minimum of two months in a community-based therapeutic treatment program.

By the third phase, there is at least six months of outpatient treatment, during which the participant lives in a half-way house or transitional residence.

In the last phase, there is supervised reintegration into the community.

"It makes a lot of sense to me," said Venango County Judge William White, whose only complaint about it is the four- to eight-month delay before treatment starts. "We use it enormously, especially on probation revocations."

Though it's a small county, Venango was one of the jurisdictions that referred the most defendants -- 19 in 2006 -- to the intermediate punishment program.

Often, the charges against defendants that Judge White sentences to the program are ones who have written bad checks or committed similar crimes.

"A lot of the people we see are hardly criminalistic, who are committing crimes to facilitate their drug problems," Judge White said. He doesn't believe that short-term treatment programs -- like 13 or 30 days --are long enough to address the underlying problems.

Westmoreland County Judge Debra Pezze agrees.

The judges in her county referred 22 defendants to intermediate punishment last year.

Judge Pezze likes the continuum of care the program offers, as well as the holistic nature of it. In addition to drug or alcohol treatment, intermediate punishment offers educational and vocational training and psychological counseling.

"Drug abuse is a sophisticated problem," she said. "Those problems land in the criminal justice system, and we're ill-equipped to deal with it without these programs."

Pennsylvania operates 27 prisons and has asked for more than half a billion dollars in next year's budget to build three more. In all, the department hopes to add almost 12,000 new beds over the next five years.

Though the trend of sending more and more people to prison hasn't stopped, it is finally starting to slow down, said Ryan King, a policy analyst for the Sentencing Project in Washington, D.C.

He attributes the changing tide to budget constraints and decades of research that show that alternative sentencing programs work.

The fiscal pressures, Mr. King said, drove the change, but it's the research that gives legislators the cover to do it.

But Wayne Welsh, a criminal justice professor at Temple University, said it took years for politicians to acknowledge the research that shows that drug courts and treatment programs are effective at reducing recidivism.

"You start talking about saving taxpayer money, then you've got the attention of the lawmakers," Mr. Welsh said.

What's important for people to remember, he said, is that there is no added benefit to society in bumping up the severity of punishment. He added that Pennsylvania has one of the longest average sentences in the country at 4.6 years.

"You have to treat the root," he said.

Most of the alternative sentencing laws, like Pennsylvania's intermediate punishment program, are very narrowly tailored. Only nonviolent offenders can be admitted, and in some states, it can only be first-time offenders.

"We don't have the political will to move the ball forward to make the legislative changes to bring substantial reductions in the prison population," Mr. King said. "The tough-on-crime movement is still very much in power.

"[But] these are important first steps."