A review of theoretical articles demonstrates that the theoretical claims of the identity status model have been greatly moderated over the past 30 years. It has been established that the model is not sufficiently specific to qualify as a developmental theory, and a teleological and unidirectional interpretation of identity development has been abandoned. The development does not have a fixed end-target, achievement, and is also not unidirectional, i.e., always proceeding from the low statuses to the high: a reverse developmental pathway is also possible. The moderation outlined here does not mean that a dominant direction in development must be denied, nor does it conflict with the fundamental developmental hypothesis of the identity status model, which (1) assumes a decrease in diffusion and foreclosure and an increase in achievement during the course of development and (2) specifies a pattern of identity status transitions underlying this progressive development. Reviews of empirical studies on identity development support the first assumption of the fundamental developmental hypothesis but not the second, owing to lack of research. An analysis of empirical studies on the relationship between identity status and psychological well-being further specifies the developmental hypothesis. In view of its associated level of psychological well-being, foreclosure emerges as another possible end-point of identity development, in addition to achievement. The developmental hypothesis and the relationship between identity status and psychological well-being are again addressed in a longitudinal study investigating relational and societal identity in a sample of 1538 Dutch adolescents. Four new identity statuses are used in this study: diffusion, closure, moratorium, and achieving commitment. The results support the first assumption of the developmental hypothesis, although not completely. For relational identity we find a decrease in diffusion and an increase in achievement and for societal identity a decrease in diffusion and an increase in closure. This means that a direction can in fact be indicated in the development of identity, but that closure can also serve as the end-point of the development, particularly for societal identity. Moreover, the domain of societal identity in general displays a less pronounced development than relational identity. This difference between relational and societal identity can be interpreted in terms of the distinction between open and closed domains of identity. In order to test the second assumption of the developmental hypothesis, the patterns of identity development were investigated for the first time in identity status research using log-linear analyses. A number of the status transitions proposed by the developmental hypothesis do not occur, and the developmental pathways are also less comprehensive. We found no indications that identity development proceeds faster in a certain period of adolescence than in other periods. However, the stability of relational identity increases, particularly in postadolescence, and a slow development of identity results in a lower level of psychological well-being.