A CRITICAL REVIEW of the literature on passage dependence concluded that contributions by both Tuinman and Pyrczak provided useful but confusing measures and concepts related to passage dependence. The major source of this confusion was traced, brought into focus, and resolved. After a vital additional element, item difficulty, was identified, the relevant concepts were integrated into a general theory of context dependence. Finally, sample items and data were discussed to illustrate the varied practical applications of the theory.