This research examined how people's ability to detect behavior change in simulated child targets is affected by their clinical experience and the assessment method they use. When using summary assessment methods that are widely employed in research and clinical practice, both inexperienced and experienced clinical staff detected changes in the overall frequency of targets' aggressive behavior, but were not uniquely influenced by changes in targets' reactions to social events. When using contextualized assessment methods that focused on conditional reactions, experienced staff showed greater sensitivity than novices to context-specific changes in targets' aggressive and prosocial reactions to aversive events. Experienced staff also showed greater sensitivity to context-specific changes in their overall impressions of change, but only for aggression. The findings show how clinically experienced judges become more attuned to ifaEuro broken vertical bar thenaEuro broken vertical bar contingencies in children's social behavior, and how summary assessment methods may hamper the detection of change processes.