ACTIVITY MEASUREMENTS SUPPORT DIMENSIONAL ASSESSMENT

The Diagnostic and Statistical Manual approach to motor excess has bee n to treat it as a categorical variable whose presence functions as an inclusion criterion. Motor excess is thought to occur primarily durin g structured settings that maximize attentional demands. Activity is r arely measured as a dimensional attribute despite availability of a wi de variety of suitable instruments for more than a decade (Tryon, 1985 ). The present study measured activity using electronic step counters in structured and unstructured school settings, commuting from home to school and back home, and at home for 2 consecutive weeks in 60 child ren selected from 450 children using Factor IV (hyperactivity) scores from the Conners Teacher Rating Scale to represent three levels of hyp eractivity. Results indicate that (a) children rated as hyperactive ar e measurably more active than children rated as normally active in uns tructured as well as structured situations, (b) measured activity corr elates consistently and substantially with rated activity in unstructu red and structured situations, and (c) a single activity factor charac terizes measured activity in all situations except for class transitio ns during school. These results and other published findings support a quantitative (dimensional) rather than qualitative (categorical) appr oach to motor excess.