Individual and Teacher/Class Effects in Aptitude Treatment Studies

Selected results from an ATI (aptitude × treatment interaction) study are presented in support of the importance of including class analyses in ATI research. This study investigated the interactive effects on performance and motivation of four motivational aptitudes and two cognitive aptitudes with a choice versus no-choice treatment manipulation. Both treatments were implemented in each of nine fourth- or fifth-grade classrooms (n = 165) over a 4-week period. Three sets of simple regression results (by treatment, within class, and between class) highlighted the differential effects of treatment on individuals versus classes and suggested substantive hypotheses about these effects.