In a study of factors in the educational environment of the home, the school, and the peer group contributing to achievement and attitudes towards schooling at the upper primary and lower secondary school levels, an opportunity arose to examine the data available for configural and curvilinear relationships. Information was collected on 11 criterion measures, 8 of which were achievement and ability measures and the remainder were measures of attitudes. Information was obtained on many structural characteristics of the home. The technique used in testing for curvilinear relationships was to determine the relative contributions of the linear and quadratic terms of the structural variables to the prediction of the achievement and attitude test scores. Testing for interaction effects among a set of 15 measures was more complex. Two different approaches were adopted. One made use of an analytic procedure which employs a computer program known as the Automatic Interaction Detector. The other involved use of a special stepwise regression procedure. The evidence gathered from the analyses reported in this paper shows that there are a few strong non linear and interaction effects which confound the simple linear model being employed in the main analyses of the investigation. (Author/JM)