When a child on the Department of Human Services' watch is killed by a caregiver, city and state officials comb through case files and interview social workers to find out what went wrong.
But the public never hears the results of those investigations.
Officials say the so-called "death reviews" are kept confidential by law to protect children, families and witnesses. Critics contend that the secrecy serves another end: to shield the agency from embarrassment and accountability.
"We do not have a system in the city of Philadelphia for an external fatality review that would be put on the public record, which we should," said Richard Gelles, dean of the University of Pennsylvania's School of Social Work.
DHS Commissioner Cheryl Ransom-Garner said that, since the records are confidential, the public must take the agency's word that it learns from its errors.
"We demonstrate it by telling you that we review ourselves internally," she said. "We have made changes to our practice and our system based on what we've learned."
The confidentiality rules may soon loosen. A new law requires states to disclose findings and information about child-abuse deaths and life-threatening injuries.
The Rendell administration, which has promised to comply, is working to get a bill passed in the final days of the legislative session.
But right now, said State Rep. Scott Petri (R., Bucks), who participated in hearings on DHS, "there is really no accountability there at all."
There is another level of death review - a youth-fatality team in each county composed of volunteer doctors and health experts.
In Pennsylvania, those reviews aren't designed to determine whether an agency mishandled a case.
"It is not part of our job to figure out whether DHS screwed up," said Pat West, a social worker who runs one of Philadelphia's death-review teams.
Instead, the teams try to identify trends that might prompt broad policy changes to prevent deaths.
Experts said such reviews, while not ideal, were useful if issued in a timely way.
But in Philadelphia, the information in the reviews is years out of date, and their publication has been sporadic.
The latest review was issued in July 2005, for deaths that occurred in 2001.
More recent data are available, but the city has not published them.
"If you know the answer as to why it takes so long to release the report, you tell me," said Paul Fink, a doctor who heads the homicide-review team.
"We are committed to putting out a more contemporaneous review, and we are committed to putting out a report annually," said Kate Maus, who directs the reviews for the city's Health Department. "You can hold us accountable to do that."