theory and research to practice. However, all psychologically based
theories should be relevant to practice. Theorists vary widely in the
extent to which they are able to translate theoretical constructs
into practical applications. It is undoubtedly the case that the rea-
son for the widespread acceptance of trait-and-factor ideas such as
those of Holland (1997) has been the ease with which his con-
structs can be implemented. For example, Holland has provided
highly useful tools in the form of inventories and linkages to occu-
pational information sources that enable counselors and psycholo-
gists to use his theory with clients.
In order to be classified as “well constructed,” a theory must meet
numerous criteria. At this juncture, no theory meets all of the stan-
dards identified. However, most theorists continue to refine their
ideas as new data emerge from research studies and as they consider
the phenomena they are trying to describe. For example, in Holland’s
latest statement of his theory (1997), he attempts to clarify and order
the constructs in his theory. In 1984, Super altered his hypotheses
about the importance of work in the lives of women and, as already
noted, in 1972 Ginzberg made substantial changes to the theory he
and his colleagues constructed (Ginzberg et al., 1951). People who
develop and study theories realize that theories are neither true or
false. They are either supported or not supported by the research they
generate. To put it differently, theories are approximations of the
complex phenomena that influence career choice and development.
The Issue of Theory Convergence
It was suggested earlier that there are many theories of career devel-
opment and occupational choice. In 1990, Osipow suggested that
the most influential ones converge in important ways. He identified
the four dominant theories as (1) Holland’s theory of personality and
vocational choices (1985, 1997), (2) Krumboltz’s social learning the-
ory (Krumboltz, 1979; Mitchell & Krumboltz, 1990), (3) Super’s
developmental theory (1990), and (4) Dawis and Lofquist’s work
adjustment theory (1984). He went on to suggest that these theories
INTRODUCTION TO THEORIES OF CAREER DEVELOPMENT AND CHOICE 11