Activity level of 13 boys (aged 9-13) from a day hospital program was measured using actometers in classroom, gym, woodshop, and group therapy settings. Ratings of Ss' activity were obtained from mothers using the Werry scale, and from six clinical staff familiar with the Ss using the Davids scale. It was predicted that activity ratings would have situationally specific relationships with actometer-measured activity level according to the rater's opportunities for observation. Comparisons between measures indicated that all clinical staff ratings correlated significantly with actometer activity in the classroom (r = .49 to r = .73), while mothers' ratings correlated significantly with actometer activity in gym (r = .67), and woodshop (r = .77), and with overall activity (r = .65), a combined measure derived from actometer scores in the four conditions tested. Five of six clinical staff raters showed significant interrater reliability (r = .58 to r = .83). Results are discussed in terms of their implications for solution of current problems in assessment of activity level and hyperactivity.