Dimensions underlying Holland's hexagon: Missing link between interests and occupations?

Abstract

Holland uses a hexagon to model relationships among his six types of vocational interests. This paper provides empirical evidence regarding the nature of the interest dimensions underlying the hexagon. Two studies are reported. Study 1 examines the extent to which two theory-based dimensions—data/ideas and things/people—fit 27 sets of intercorrelations for Holland's types. Three of the data sets involve the mean scores of career groups (total of 228 groups and 35,060 individuals); 24 involve the scores for individuals (total of 11,275). Study 2 explores the heuristic value of the data/ideas and things/people dimensions by determining whether they contribute to the understanding of why interest inventories work. Two data sets covering a total of 563 occupations are used to calculate correlations between the vocational interests of persons and the tasks which characterize the persons' occupations. Each occupation's principal work tasks are determined from job analysis data obtained from the U.S. Department of Labor. Study 1 results provide substantial support for the theory-based dimensions. Study 2 results suggest that interest inventories "work" primarily because they tap activity preferences which parallel work tasks. Counseling and research applications of the data/ideas and things/people dimensions are suggested and implications for interest assessment are noted.