Exploratory and confirmatory factor analyses of the DIAL-3: What does this “developmental screener” really measure?

To examine the convergent and discriminant validity of the scales on the Developmental Indicators for the Assessment of Learning—Third Edition [DIAL-3; Mardell-Czudnowski, C., and Goldenberg, D.S. (1998). Developmental indicators for the assessment of learning—third edition. Circle Pines, MN: American Guidance Service, Inc.], exploratory and confirmatory factor analyses were performed on randomly selected subsamples of 2012 children who attended Head Start. Exploratory factor analysis yielded three factors, labeled Verbal Ability, Nonverbal Ability, and Achievement, which collectively accounted for 56% of the variance in children's performances. Confirmatory factor analysis evaluated this empirically-derived model and the conceptually-derived model of the authors of the DIAL-3 in a separate subsample of children. Although neither model explained the data extremely well, the empirically-derived model characterized children's performances better than the conceptually-derived model, e.g., CFIs = .90 and .85, RMSEAs = .07 and .10, respectively. The discussion highlights an alternative conceptualization of the DIAL-3, potential uses of the factor scores, ideas for consideration during the next revision of the DIAL-3, and the need for additional validity research.