Dimension and exercise variance in assessment center scores: a large-scale evaluation of multitrait-multimethod studies.

This study addresses 3 questions regarding assessment center construct validity: (a) Are assessment center ratings best thought of as reflecting dimension constructs (dimension model), exercises (exercise model), or a combination? (b) To what extent do dimensions or exercises account for variance? (c) Which design characteristics increase dimension variance? To this end, a large set of multitrait-multimethod studies (N = 34) were analyzed, showing that assessment center ratings were best represented (i.e., in terms of fit and admissible solutions) by a model with correlated dimensions and exercises specified as correlated uniquenesses. In this model, dimension variance equals exercise variance. Significantly more dimension variance was found when fewer dimensions were used and when assessors were psychologists. Use of behavioral checklists, a lower dimension-exercise ratio, and similar exercises also increased dimension variance.