especially considering that a large number of studies have been devoted to an in-depth analysis of this model (by V. V. Davydov, D. I. Fel'dshtein, B. D. El'konin, and others), and attempts to refine or empirically verify its propositions have been the aim of almost all experimental...
of combinations: a model with five dichotomous variables, for example, would have 32 possible types. However, once the researcher begins to categorize extant cases in a preliminary way into particular types, it often becomes possible to narrow the range of cases of interest for study. Many ...