Nominal Weights Mean Equating

Abstract

The authors introduced nominal weights mean equating, a simplified version of Tucker equating, as an alternative for dealing with very small samples. The authors then conducted three simulation studies to compare nominal weights mean equating to six other equating methods under the nonequivalent groups anchor test design with sample sizes of 20, 50, and 80 examinees. Results showed that nominal weights mean equating was generally the most effective. Nominal weights mean equating was, furthermore, never among the least effective methods in any condition, indicating its utility across a wide variety of contexts. Circle-arc equating, another recently developed method, also showed a great deal of promise. The identity function (i.e., no equating) was adequate only when test forms were nearly equivalent in difficulty.