“…Holland and others have conducted a number of studies related to the theory and its constructs. These studies have generally used one of four empirical approaches: (a) 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, 1960(Holland, , 1962(Holland, , 1963aWall, Osipow, & Ashby, 1967); (b) assessment of the range of personal orientation of a variety of educational, vocational, and hospitalized groups (Fairweather, Simon, Gebhard, Weingarten, Holland, Sanders, Stone, & Reahl, 1960;Holland, 1958); (c) investigation of the relationship between VPI scale scores and self-ratings or self-descriptions on traits which the various scales are assumed to measure (Holland, 1962(Holland, , 1963b(Holland, , 1964; and (d) investigation of the associations and relationships of scale scores with various external criteria (Astin, 1963;Astin & Holland, 1961;Forsyth & Fairweather, 1961;Holland, 1958Holland, , 1962Lopez, 1962;Osipow, Ashby, & Wall, 1966). In general, the results of these studies lend support to the meanings attributed to the scales.…”