This study investigates the effects of alternate types of curriculum and counseling treatment on elementary school children categorized into six temperament-attitude clusters. Through a second-order factor analysis of a multi-trait multi-source assessment instrument (The Barclay Classroom Climate Inventory), six cluster groups of characteristics based on self-report, peer nominations and teacher judgments were identified. Utilizing three sets of pre-post longitudinal data, an analysis of covariance was completed on scale and factor scores partialing out the effects of sex, treatment and cluster group. Similar nonparametric methods were used for indicators of problem behavior. A number of significant three-way interactions was obtained. A value judgment was made concerning the growth direction (positive or negative) of means changes for these variables and groups. The results of the study suggest that temperament-aptitude clusters present a mediating effect on outcomes of educational or counseling treatments. What works well as an intervention for one group appears to block development for another group. Evidence of the replicability of the findings is presented and study limitations are discussed. (Author/CM)