Minnesota spends far less than most states to lock up its youngest offenders, thanks in part to diversionary programs that try to keep juveniles out of prison.

Even so, says a new report that quantifies the costs of juvenile incarceration, the collateral costs on young lives can be lasting and substantial.

The findings of the Justice Policy Institute, published Tuesday, seem to confirm the success of the state's use of diversionary programs and other tactics, observers said.

Marc Schindler, executive director of the Washington-based research and advocacy group, said that despite a nearly 45 percent drop in juvenile crime nationwide, incarceration of the country's non­violent youth offenders "continues to be overused."

Minnesota spent an average of $104,839 a year to house, feed and guard each juvenile inmate, according to the report, titled "Sticker Shock: Calculating the Full Price Tag for Youth Incarceration." Overall, the state spent far less per year than the national average of $148,767, but more than twice the amount of the lowest spender, Louisiana, whose prison system is largely privately owned. New York is far and away the national leader in juvenile incarceration spending, with annual costs approaching $353,000 per inmate.

At a time when states are looking for creative ways to slash prison costs and lower their inmate populations, Minnesota is being held up by some as a model.

Much of the credit for this, officials say, goes to recent legislation, funding and the efficacy of such diversion programs as the Juvenile Detention Alternatives Initiative, which among other things reminds juveniles of upcoming court dates with a timely phone call.

"I think we've also realized that incarcerating juveniles, short of serious crimes, is not a good idea," said Hennepin County Attorney Mike Freeman.

As a result of such initiatives, fewer young people see prison time for such nonviolent offenses as curfew violations and truancy, he said.

Instead, juvenile detention staffers weigh whether an offender should be held in secure detention or is eligible for a community-based alternative. He said it was unclear why Minnesota's costs were so low compared with other states.

Teresa Nelson, legal counsel of the Minnesota chapter of the American Civil Liberties Union, said she was impressed by the study's ambitious scope, which sought to calculate "not only how much does it cost to turn that key and lock somebody up but also the impact on society."

Nelson also drew attention to the racial disparities in incarceration rates included in the report's findings, which suggested that black youths are nearly five times more likely to be imprisoned than whites for similar offenses, while Latinos are nearly twice as likely. Nelson said her eye was drawn to that statistic since Minnesota has among the nation's highest rates of racial disparities in its correctional system.

The report calculated that the "long-term costs" of juvenile imprisonment, including the psychological toll of incarceration, lost future earnings, increased health care costs and higher recidivism rates, range from $8 billion to $21 billion annually.

State Department of Corrections officials declined to comment on the research because they had not read the full report, a spokesman said Tuesday afternoon.

In Minnesota, as in the rest of the country, there has been a precipitous drop in juvenile crime. From 1998 to 2011, the number of juvenile arrests plummeted from 79,584 to 36,192, as the state launched several initiatives geared at young offenders, including mental health screenings, risk-assessment tools to determine community supervision levels and transition plans for those looking to reintegrate into society after serving prison time.

Minneapolis saw juvenile arrests fall 65 percent between 2000 and 2013, Freeman said. Sixty percent fewer minors were admitted to juvenile detention facilities in that time.

"Kids are very influenced by their environment and their circumstances. Kids need their families, they need their peers and sometimes when you take kids out of their homes and you send them to a jail-like facility, they learn things there that it would be better that they didn't learn," Freeman said.

The report offered a range of recommendations for improving the juvenile detention system, including shifting funding from "confinement" to more data-proven tactics.

"There are circumstances when a young person may need to be placed out of the home and confined," the report stated. "That said, incarceration should be the last resort, not the first resort, for every juvenile justice system in the country."