“…Holland and other investigators have conducted a number of studies related to the theory and its constructs. These studies have generally used one of four empirical approaches; (l) the investigation of the relationship between personal orientation as measured by the Vocational Preference Inventory (VPI; Holland, 1965) and other inventories and educational choice (Holland,i960, 1962(Holland,i960, , 1963aWall, Osipow, and Ashby, 1967); (2) assessment of the range of personal orientation of a variety of educational, vocational, and hospitalized groups (Fairweather, Simon, Gebhard, Weingarten, Holland, Sanders, Stone, and Reahl, i960;Holland, 1958)i (3 ) investigation of the relationship between VPI scale scores and self-ratings on self-description on traits which the various scales are assumed to measure (Holland, 1962(Holland, , 1963b and (h) investigation of the associations and relationships of scale scores with various external criteria (Astin, 1963;Astin and Holland, 196l;Forsyth and Fairweather, 1961;Holland, 1958Holland, , 1962Lopez, 1962;Osipow, Ashby and Wall, 1966). In general, the results of these studies lend support to the meanings attri buted to the scales.…”