During the past decade and a half, a great deal of research has posited a developmental sequence approach in second language acquisition. Much of this research has proposed that certain linguistic structures are acquired in a natural immutable order while other linguistic structures are acquired variably as a result of a learner's orientation (Clahsen, Meisel, & Pienemann, 1983; Meisel, Clahsen, & Pienemann, 1981; Pienemann, 1984, 1985, 1987; Pienemann & Johnston, 1987). Proposals have been made for extending the model into language assessment and pedagogy (Clahsen, 1985; Pienemann, 1984, 1992; Pienemann & Johnston, 1987). The present study reexamines the original social-psychological research upon which the multidimensional model is based and shows that it is incorrect due to faulty analyses. Further, it examines the limited applicability and generalizability of the developmental sequence approach for assessment and pedagogy.