behavior, total problems, were also analyzed and include items from all subscales, including social problems, thought problems, and attention problems subscales. Given significant positive skew observed of raw CBCL scores, log-transformations of internalizing, externalizing, and total problems scales were analyzed. Consistent with Achenbach and Rescorla (2001), data were considered valid if fewer than 8 items were missing, excluding open-ended items. Valid mother and twin father reports were both available for 16 of 411 PACER families; for these families, mother report was used.
