Because latent trait models require that large numbers of items be calibrated or that testing of the same large group be repeated, item parameter estimates are often obtained by administering separate tests to different groups and "linking" the results to construct an adequate item pool. Four issues were studied, based upon the analysis…

Researchers and program evaluators would often like to use a particular instrument, but do not because it is too long or would require too much testing time. Having a validated set of objective procedures for reducing the size of an instrument could improve many research and evaluation efforts. This paper reports the results of test reduction or…