“Thumbs up”: response bias in assessing vocational interests using verbal and pictorial formats

This study examined how acquiescent responding influences vocational-interest items and evaluated the equivalence of a new Pictorial Inventory of Vocational Interests (PIVI) and a parallel verbal form (VIVI). A sample of 179 participants completed the instruments and a brief set of “bogus” preference items indexing acquiescence. Using SEM, we fit baseline CFA models and MIMIC models with the acquiescence index predicting item responses. Internal-structure analyses showed acceptable fit consistent with the RIASEC model in both formats, with adequate factor loadings. We then tested invariance of item parameters across formats (configural, metric, scalar): model fit changed minimally when factor loadings and thresholds were constrained equal (ΔCFI < .01; ΔRMSEA < .01), supporting metric and scalar invariance. Acquiescence exerted direct effects on multiple items in both formats, with the pictorial version slightly less vulnerable. At the scale level, acquiescence correlated more strongly with profile elevation than with differentiation. Overall, pictorial assessments appear to be a viable alternative for measuring vocational interests, and the results underscore the importance of modeling response bias when measuring vocational interests.