HARRISBURG — Even as the number of people in state prisons across the country has fallen for the first time in almost four decades, Pennsylvania's prison population is on the increase.

Pennsylvania had a 4.3 percent rise in the number of prisoners last year, the Pew Center on the States said in a study issued last week. Across the country, state prisons nationwide held roughly 1.4 million inmates at the beginning of the year, 0.4 percent fewer than there were at the end of 2008 — the first year-to-year drop since 1972, the study said.

The center attributed the decline in part to states adopting guidelines reflecting research that low-level offenders and those who have committed technical parole violations are more effectively handled in community programs.

"We are starting to see a triumph of science over sound bites," said Adam Gelb, director of the center's Public Safety Performance project. "State leaders are reaching across the aisle and coming up with research-based corrections strategies for nonviolent offenders."

In Pennsylvania, the inmate population has increased from 8,243 to 51,326 over the past three decades, according to the state Department of Corrections. Adding to the increase was Gov. Rendell's 2008 moratorium on paroles after a paroled felon killed a Philadelphia police officer.

Due to prison overcrowding, the commonwealth last month began sending inmates to prisons in Virginia and Michigan and plans to place 2,000 prisoners in other states by the end of next month.