Consultant James Austin told the legislative money committees Wednesday that Nevada is significantly below national averages for the number of inmates released on parole and probation.
He said Nevada judges grant probation at a rate of 716 per 100,000 population - less than half the national average of 1,862. He said the state's parole rate is also low - 243 compared to 317 nationally.
But Nevada's incarceration rate, Austin said, is significantly higher than the nation's average - 471 per 100,000 population compared to 422.
He said these factors are a big force driving the state's rising prison population but don't explain last year's sudden increase, which expanded the prison population by 900 inmates to more than 11,400 last December. Female inmates increased by 16 percent during that period.
"It looks like that's settled down now so we're hoping it's a one-time phenomenon," he told the committee.
Austin said if the state wants to control the prison population, policy makers should look at who is in prison and how to get them out.
He told the subcommittee even a small change in how long the average inmate stays in prison can make a big difference. He said the current average stay is about 26 months.
"If that drops to 24 months, your prison population would drop 10 percent," he said. "That's how important length of stay is."
"The youthful offender is the one you want to be concerned about," he said. "The good thing about criminals - who are mostly men - is that they burn out with age. It's the youthful offender who is very likely to recidivate so you want to throw all the treatment at them you can."
He said those between 18 and 25 commit the most serious crimes and that the risk in most cases declines sharply after an inmate reaches age 40.
"After that, stick a fork in them, they're pretty much done. There are exceptions, of course, like sex offenders," Austin said.
But he said there are probably a substantial number of older inmates in the prison system who could safely be released on parole.
Austin said Nevada's male prison population is projected to grow 3.1 percent a year through 2015 - the women's population faster at about 3.8 percent annually. He said that is far higher than the 1 percent to 2 percent most states are experiencing, but its primarily because Nevada is the fastest growing state in the nation.
He said Nevada's healthy economy should help keep crime rates under control.
"The economy has a lot to do with crime rates," said Austin. "It also has a lot to do with recidivism rates. Inmates need jobs."
He presented results of a decade-long comparison he did in Alabama which showed a close match between crime rates and fluctuations in welfare caseloads.
He said all that has a lot to do with what experts call "social stress" factors - including unemployment rates.
"If you want to go after your crime rates, go after those indicators," he said.