Does Sparseness Matter? Examining the Use of Generalizability Theory and Many-Facet Rasch Measurement in Sparse Rating Designs.

Sparse rating designs, where each examinee's performance is scored by a small proportion of raters, are prevalent in practical performance assessments. However, relatively little research has focused on the degree to which different analytic techniques alert researchers to rater effects in such designs. We used a simulation study to compare the information provided by two popular approaches: Generalizability theory (G theory) and Many-Facet Rasch (MFR) measurement. In previous comparisons, researchers used complete data that were not simulated-thus limiting their ability to manipulate characteristics such as rater effects, and to understand the impact of incomplete data on the results. Both approaches provided information about rating quality in sparse designs, but the MFR approach highlighted rater effects related to centrality and bias more readily than G theory.