National data on child abuse fatalities show that a child is more than twice as likely to die of abuse in foster care than in the general population.

A study of reported abuse in Baltimore found the rate of “substantiated” cases of sexual abuse in foster care more than four times higher than the rate in the general population. Using the same methodology, an Indiana study found three times more physical abuse and twice the rate of sexual abuse in foster homes than in the general population. In group homes there was more than ten times the rate of physical abuse and more than 28 times the rate of sexual abuse as in the general population, in part because so many children in the homes abused each other.

Those studies deal only with reported maltreatment. The actual...