Factors affecting the variability of IRT equating coefficients

Knowing the effect of the factors that can influence the variability of the equating coefficients is an important tool for the development of the linkage plans. This paper explores the effect of various factors on the variability of item response theory equating coefficients. The factors studied are the sample size, the number of common items, the length of the chain, and the possibility of averaging the equating transformations related to different paths that connect the same two forms. Both asymptotic and simulations results are provided.