Numerous marriage formation models have been proposed, and previous attempts to select among them empirically have produced equivocal results. Herein two models, which had been appraised as most promising on the basis of their logical properties, are analyzed to identify conditions under which they yield predictions sufficiently different as to permit unambiguous determination that one or other is wrong. The conditions thus identified involve a relatively large cohort rising through successive age groups, conditions which will be empirically observed during the next several years. Implications of the models' differences, when used to anticipate future fertility rather than marriages per se, are also considered.