Assessing measurement equivalence across rating sources: a multitrait-multirater approach.

Research examining the structure of multisource performance ratings has demonstrated that ratings are a direct function of both who is doing the rating (rating source) as well as what is being rated (performance dimension). A separate line of research has focused on the extent to which performance ratings are equivalent across sources. To date no research has examined the measurement equivalence of multisource ratings within the context of both dimension and rating source direct effects on ratings. We examine the impact of both performance dimension and rating source as well as the degree of measurement equivalence across sources. Results indicate that (a) the impact of the underlying performance dimension is the same across rating sources, (b) the impact of rating source is substantial and only slightly smaller than the impact of the underlying performance dimension, and (c) the impact of rating source differs substantially depending on the source.