Score comparability of a state reading assessment across selected groups of students with disabilities

This study investigated the factorial invariance of scores from a 7th-grade state reading assessment across general education students and selected groups of students with disabilities. Confirmatory factor analysis was used to assess the fit of a 2-factor model to each of the 4 groups. In addition to overall fit of this model, 5 levels of constraint, including equal factor loadings, intercepts, error variances, factor variances, and factor covariances, were investigated. Invariance across the factor loadings and intercepts was supported across the groups of students with disabilities and general education students. Invariance for these groups was not supported for the error variances. For the students with mental retardation, the lack of fit of the 2-factor model and the observed score results suggested a mismatch between the difficulty level of this test and the ability level of these students. Although the results generally supported the score comparability of the reading assessment across these groups, further research is needed into the nature of the larger error variances for the student with disabilities groups and into accommodations and modifications for the students with mental retardation.