Treatments for disruptive behaviors are often guided by parent reports on questionnaires, rather than by multiple methods of assessment. Professional observations and clinic analogs exist to complement questionnaires, but parents can also collect useful behavioral observations to inform and guide treatment. Two parent observation methods of child aggression and noncompliance were compared: the Parent Daily Report (PDR) and Behavior Record Cards (BRC). Parents tracked misbehavior for 2 weeks using the PDR or BRC. BRC data proved to be more accurate, though both systems yielded strong reliability and moderate validity. The BRC is recommended to clinicians on empirical and conceptual grounds. (Contains 4 tables.)