Children who end up in Pennsylvania's foster care system encounter many obstacles to finding stable, nurturing homes, a statewide children's advocacy group said in a report.

Nearly 30 percent of all children statewide who are reunited with their families end up returning to foster care within a year, and that rate is as high as 40 percent in some counties, according to the report released yesterday by Pennsylvania Partnerships for Children.

In Allegheny County, the re-entry rate was about 27 percent, slightly lower than the state average.

Joan Benso, president and chief executive officer of the partnership, said the statewide findings indicate that child welfare agencies must work harder to address underlying family problems that result in abuse and neglect before allowing foster children to reunite with their birth families.

"One of the primary reasons a child is removed from the home is substance abuse," she said. "If the parent doesn't get effective substance abuse services, the notion that you're going to successfully reunite [the parent with the child] is pretty slim."

About 20,000 children are in foster care at any given time and typically stay in the system for 16 months, according to the report. The largest share, 47 percent, live in foster homes with non-relatives. A quarter live in institutions and group homes, and 22 percent have been placed with relatives.

In Allegheny County, children stay in the foster system for 20 months, longer than in most counties, according to the report. The partnership said the county should move more quickly to create "permanency" for children in the system.

Marc Cherna, head of the Department of Human Services, said that 20-month figure is largely due to older adolescents, some of whom are not being removed as quickly from foster care because the county is working with them to prepare them for higher education, adulthood and self-sufficiency.

"We're trying to engage these adolescents," he said.

But, he agreed, "I think 20 months is still too long."

The partnership also said Allegheny does a better job than most counties of placing children with relatives, a process called "kinship care."

The state average for children placed with relatives is about 22 percent, but in Allegheny County it's 39 percent.

Mr. Cherna said he welcomed the report, the first of its kind in the state.

"I think it's good to shine a light on this stuff," he said.