At their computer terminals, Winzer and her colleagues begin translating the allegations into answers that fit neatly into the multiple choice questions asked by the computer program called Structured Decision Making, or SDM.

If a parent has a drug or alcohol problem, the computer adds one point to the score; no prior referrals subtracts a point. An allegation of excessive discipline, defined as

As a case moves from one point to the next, the answers to SDM's multiple questionnaires -- on such topics as the child's risk of abuse and existing safety factors in the home -- build a complete dossier. Because Los Angeles County's child protection system works like an assembly line, no single person follows a case from beginning to end; only the computer does.

But SDM is only as good as the information humans enter into it. Since it went into widespread use in L.A. County seven years ago, there have still been high-profile cases of children left in abusive households.

"If the social workers don't do their investigation properly, if they don't analyze the case thoroughly, it will be garbage in and garbage out," said Trish Ploehn, director of the family services department.

Another major question is why investigations involving black children result in detentions four times more often than investigations of white children. Although a racial disparity existed before the switch to SDM, department of Children and Family Services officials had hoped it would be mitigated by the computer.

Instead, the disparity has worsened slightly over the course of SDM's use.

Now suspicion is centering on use of factors that may disadvantage black families. For example, the system counts prior referrals against a parent even if they are not substantiated, though substantiated referrals have greater weight. Studies show that black families are more likely to be the subject of referrals, perhaps because of bias and because they more often come into contact with mandated reporters such as social service workers and police.