The problem of factor score indeterminacy implies that the factor and the error scores cannot be completely disentangled in the factor model. It is therefore proposed to compute Harman's factor score predictor that contains an additive combination of factor and error variance. This additive combination is discussed in the framework of classical…

Seven papers on technical and practical issues in equating are presented. Problems related to the use of conventional and item response theory equating methods, using pre- and post-smoothing to increase equipercentile equating's precision, and linear equating models for common-item nonequivalent-population design are discussed. (SLD)

Issues concerning equating test scores are discussed in an introduction, four papers, and two commentaries. Equating methods research, sampling errors, linear equating, population differences, sources of equating errors, and a circular equating paradigm are considered. (SLD)