The Estimation of Variance Components in Generalizability Studies: A Resampling Approach

The accurate estimation of variance components is essential for studying the reliability of a measurement procedure in generalizability theory. Previous research has shown that errors in estimation of variance components lead to erroneous interpretations. This is particularly true with small samples, nonnormal data, and unbalanced designs. This study explores a resampling procedure for obtaining estimates of variance components. The results suggest that the proposed method is useful when most needed—with small samples, nonnormal distributions, and unbalanced designs.