Using the self-directed search in research : selecting a representative pool of items to measure vocational interests

Abstract

Using Item Response Theory (IRT) and Confirmatory Factor Analysis (CFA), the goal of this study was to select a reduced pool of items from the French Canadian version of the Self-Directed Search—Activities Section (Holland, Fritzsche, & Powell, 1994). Two studies were conducted. Results of Study 1, involving 727 French Canadian students, showed that the psychometric qualities of the 66-item French Canadian version are equivalent to those of the original English version. Based on IRT and factor loadings derived from a CFA, 24 items were selected from the original 66 items. In Study 2 (n = 339 French Canadian young adults), we tested and obtained support for the construct validity of the 24 selected items using CFA and correlational analyses among interests’ dimensions. We concluded that the selected pool of items accurately captured Holland’s theoretical framework and showed adequate psychometrics qualities and construct validity.