Two cohorts of fifth form boys were followed through school into their first year out of school. An attempt was made to test Super's thesis that entry into a career is part of a developmental process. Super's writings provided the basis for the identification and classification of indices of vocational maturity in the fifth form. The thesis postulated that the efficiency of these indices in predicting vocational adjustment, in the first year out of school, provided a crucial test of Super's developmental theory. Forward regression, a variation of stepwise regression, was used to identify efficient predictors. In general, it was not possible to predict adjustment in the first year of a career from the proposed indices of vocational maturity. It was possible to predict, with a fair degree of accuracy, the level of occupational attainment from the boys' educational attainment and aspirations. The results raise some doubts about the tenability of a developmental theory, if the goal is vocational adjustment. The findings are discussed within the context of an analysis of the nature of developmental theories in the social sciences.