Problems in the measurement of latent variables (LVs) in structural equations causal models are presented, with examples from recent empirical studies. Main issues addressed are (1) two general types of increased operative variables; (2) criteria for indicators of LVs; and (3) disattenuation effects in LV models. (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)

The importance of regression diagnostics in detecting influential data points is discussed, and five statistics are recommended for the applied researcher. The suggested diagnostics were used on a dataset of 24 subjects, and effects were analyzed. Colinearity-based diagnostics and diagnostics for a variety of procedures are discussed. (SLD)