A linear regression approach to determining the number of factors in factor analytic solutions is presented. It provides objectivity while producing the same results as the visual scree test. Experience with the method to date indicates that the results are consistent with visual solutions. (SLD)

After a brief review of the contributions of factor analysis and regional analysis to the elaboration of the structures of spatial abilities, a facet design and regional model for spatial abilities are presented. A cylindrical-wedge model is proposed to represent the correlational structure of spatial ability tests. (SLD)