The findings show that the Weekly Problems Scale-Child Version (WPS-C) and the Weekly Problems Scale-Parent Version (WPS-P) demonstrated adequate internal consistency, temporal stability, and construct validity. They show significant promise as research and clinical assessment tools for use with youth who have been sexually abused and their nonoffending parents. The WPS-C and the WPS-P were developed for use as an initial assessment and as a repeated measure of the functioning of youth who had been sexually abused. Both instruments were developed from a review of existing literature to monitor the weekly progress of the child and family in treatment. They assess the three critical target areas impacted by sexual abuse: the individual, relationships, and sexual behavior. The scale items focus on common areas of difficulty in this population: negative mood, problem behavior, problem interactions with others, and abuse-related emotional and communication problems. Participants were 64 children and adolescents who were sexually abused and 64 of their nonoffending parents. They were engaged in cognitive-behavioral group treatment at an outpatient clinic. Families were recruited by contacting appropriate community agencies about Project SAFE (Sexual Abuse Family Education) and mailing brochures to provide information on the treatment. Families who participated in Project SAFE treatment groups completed the WPS-C and WPS-P at the pretreatment and posttreatment assessments and weekly throughout the course of treatment. Fifty youth who were sexually abused and 48 parents received the standardized 12-session group treatment. Procedures used in sessions were psychoeducational, skill building, problem solving, and supportive. 8 tables and 54 references