Some Generalizations about Generalization

Abstract

Three fallacies about generalization are that so-called basic research is more generalizable than applied research, that general findings are immediately useful for design purposes, and that the use of taxonomies increases the generalizability of human factors studies. Some factors that limit generalizability are the use of unrepresentative subjects, insufficient training subjects receive before measurements are begun, inadequate sampling of tasks and situations, inappropriate selection of dependent variables, long-term changes in the world of work, and artifacts attributable to the measurement process itself In designing a study to predict behavior in a specific application, the guiding principle is similarity. The study should be as similar as possible to the real situation. Two principles should be followed to design studies whose findings can be extrapolated to a wide range of situations: (1) design heterogeneity into the studies and (2) replicate earlier studies with variations in subjects, variables, or procedures.