Analysis of responses to vocational interest items: A study of Australian high school students

The vocational interests of 2,709 male and female high school students in A ustralia were examined using a Rasch model of item responding. The present study used a national probability sample of Australian youth. Participants completed a 24-item questionnaire that reflected the vocational interest ty pology of Holland. Item response analysis was used to determine the locatio n of the four questions that comprised each of the vocational scales. Scale s and items conformed generally to the measurement model. Infit mean square s centred on 1.0 and separability was satisfactory for all scales (0.85 to 0.99) except the Investigative scale. The analysis of items using a Rasch m odel provided new information on how individuals responded to items and the complexity of responses within interest categories. It is argued that simp le raw scores or summing scores may not offer a valid basis for assessment of interests.