The research in this monograph was stimulated by the need for an objective, standardized measure of vocational maturity which would provide an empirical referent for the conceptual terms of vocational development theory. The instrument constructed for this purpose is the Vocational Development Inventory, which consists of a Competence Test and the Attitude Scale. The former is designed to assess the cognitive components of vocational maturity; it has not been completed yet. The latter is intended to define operationally the cognitive elements in vocational maturity. Findings include the following: (1) the relationship of items to grade was stronger than it was to age; (2) there was a trend for item endorsements to change from True to False across grades; (3) there were two"stages" in the item curves, between the 6th and 7th grades and the 9th and 10th grades; and (4) a subset of items which were unrelated to age or grade and which elicited deviant responses might constitute an index of vocational maladjustment. The Vocational Development Project was established, also, to implement a program of different, but interrelated types of research: survey, technique, theoretical, and applied. (Author/TA)