This article continues a series of analyses using of developed by John Holland (1966, 1973, 1985, 1997) to examine patterns of student stability and change inherent in college experience--as part of an effort to understand satisfaction, learning, and retention of college students (see Smart, Feldman & Ethington, 2000; Feldman, Smart & Ethington, 1999; and Feldman, Ethington & Smart, 2001). The underlying basis of Holland's theory is that human behavior is a function of interaction between individuals and their environments. The theory focuses on an assessment of individuals, their environments, and interaction or fit between individuals, and their environments. Three specific assumptions are associated with these three essential components of theory: (1) people tend to choose environments compatible with their personality types; (2) environments tend to reinforce and reward different patterns of abilities and interests; and (3) people tend to flourish in environments that are congruent with their dominant personality types. Most research assessing validity of three assumptions has tended to examine merits of each assumption separately. The collective evidence from literally hundreds of studies over past three decades or so has been summarized in several literature syntheses and meta-analyses (see, for example, Assouline & Meir, 1987; Holland, 1985, 1997; Spokane, 1985, 1996; Tranberg, Slane, & Ekeberg, 1993; Walsh & Holland, 1992). Because Holland's theory intends to explain vocational behavior, most evidence of validity of basic assumptions of theory has been derived from studies of employed adults. Moreover, attention has been directed primarily to vocational choices of individuals and significance of these choices for their vocational stability, satisfaction, and success. This dominant focus on individuals may be understood as a consequence of primary focus of theory itself and scholarly interests of those who have conducted much of relevant research. As a theory of careers, Holland's work is intended primarily to be of assistance to individuals in their search for careers that are satisfying and rewarding, and research on theory reflects this orientation toward individuals. The vast bulk of research literature in this area concentrates on validity of personality types and their searching behavior (the self-selection assumption) and on consequences of individuals' choices of congruent or incongruent vocational environments (the congruence assumption) rather than on reward and reinforcement patterns of vocational environments (the socialization assumption). Holland has acknowledged this differential emphasis in research literature, noting that the environmental models are only occasionally studied 160). As Walsh and Holland (1992) have put it: We view theory as primarily psychological in nature and one in which personality variables are most powerful and influential .... The theory tends to emphasize person variables and [to be] lean on concept of reinforcement ... (p. 63). Given psychological orientation of Holland's theory and of those who have conducted most of research on theory, it is not surprising that work environments (in general) and interpersonal and social structural patterns of environmental reinforcement (in particular) have not been of central interest. While his theory is intended to explain vocational behavior, Holland has noted repeatedly that theory and its basic assumptions are equally applicable to educational settings such as college and universities. The research evidence supporting basic assumptions of Holland's theory is sparser as it pertains to college students; even so, dozens of relevant studies have been conducted over past three decades (as reviewed in Smart et al. …