The nation's 500,000 children in foster care languish for years in temporary homes because juvenile and family courts do not adequately track their caseloads, according to a one-year national study released yesterday by the Pew Commission on Children in Foster Care.

The commission, a nonpartisan panel of national child welfare experts, also found that federal funding is geared toward keeping the children in foster placements and that too few dollars are spent to support adoptions and preventive services.

"Every child needs a safe, permanent family," said Bill Frenzel, commission chairman. "Our recommendations focus on what states and courts have to do to help children."

Children remain in foster care an average of three years and change families an average of three times, according to the study.

In a ranking of the states, the District and Puerto Rico, Maryland had the 10th-largest foster care population, about 12,500 children. Virginia was ranked 25th, with 6,800 foster children, and the District was 34th, with about 3,300.

The commission, which is supported by a grant from the Pew Charitable Trusts to the Georgetown University Public Policy Institute, looked at the role of the courts and federal funding because they play important roles in the foster care system.

No child enters or leaves foster care except by judicial order. The commission said the nation's courts lack procedures to monitor the system's revolving-door tendencies. Too often, children return to foster care after being reunited with their families, adopted or placed with a legal guardian.

The panel recommended that judges track and analyze caseloads to look for ways to avoid unnecessary delays in deciding placements. It called on state court leaders to provide more oversight of child welfare cases. And the courts are urged to involve parents and other relatives in child welfare hearings whose complexity can discourage their participation.

The report also suggested major changes in how states spend federal foster care money.

The study recommended that Congress redirect federal spending on foster care and create a Safe Children, Strong Families Grant, which would require $200 million in new federal money in the first year. Under the grant program, state foster care systems would be able to spend federal funds on such services as substance abuse prevention and mental health care.

If a state reduced the number of children in foster care, it would be able to reinvest unspent state and federal funds in services for foster children, according to the study recommendations.

Many child advocates praised the report, which commission members said they would take to congressional leaders and advocates as part of the push for reforms.

But Richard Wexler of the National Coalition for Child Protection Reform, an Alexandria-based nonprofit organization, said the proposed grant program did not set strict guidelines on spending.

Wexler said there is nothing to stop state foster care systems from spending money intended for prevention on operating expenses. "They've left the prevention money vulnerable to attack," he said.