Optimal Linking Design for Response Model Parameters

Linking functions adjust for differences between identifiability restrictions used in different instances of the estimation of item response model parameters. These adjustments are necessary when results from those instances are to be compared. As linking functions are derived from estimated item response model parameters, parameter estimation error automatically propagates into linking error. This article explores an optimal linking design approach in which mixed-integer programming is used to select linking items to minimize linking error. Results indicate that the method holds promise for selection of linking items.