The currently dominant, myopic approach to statistical analysis in psychology is based on analysis of inter-individual variation. Differences between subjects drawn from a population of subjects provide the information to make inferences about states of affairs at the population level. For instance, the factor structure of a personality test is determined by drawing a random sample of subjects from the population of interest, estimating the item correlation matrix by pooling across the scores of sampled subjects, and generalizing the results of the ensuing factor analysis to the population of subjects.