In Kentucky and New Jersey, we examined a number of subgroups of families to determine whether we could detect differences between experimental and control groups on placement and substantiated allegations subsequent to random assignment within each subgroup. Most of the subgroups were defined in terms of problems of the family, for example, substance abuse, financial difficulties, and depression. The number of cases in Tennessee was not sufficient to support subgroup analysis. In only one subgroup was a significant difference found between experimental and control cases: among single mothers in New Jersey, those in the experimental group were less likely to have a subsequent substantiated allegation than those in the control group. No subgroups were found in which there were effects on placement. Hence, the effort to find subgroups for which family preservation service was successful in reducing placement was not successful.