The problems involved in the measurement of vocational maturity are complicated by the hypothesized developmental nature of the behaviors to be quantified. One major problem mentioned is that of formulating a measurement model which incorporates the merits of established approaches to test construction yet circumvents their shortcomings. A brief review of approaches to such test construction is presented with some of the criticisms which have been made of them. A number of substantive and psychometric problems in the measurement of vocational maturity are identified. It is emphasized that their solutions are provisional and tentative, subject to further revision as the relevant data are gathered and analyzed. Problems which are not discussed include such imponderables as how to partition developmental score variance from stable and error variance, and how to control for the effects of environmental change and repeated measurements in longitudinal designs. (Author/BW)