These studies in test adequacy focus on two problems: procedures for estimating reliability, and techniques for identifying ineffective distractors. Fourteen papers are presented on recent advances in measuring achievement (a response to Molenaar); "an extension of the Dirichlet-multinomial model that allows true score and guessing to be correlated"; results on an answer-until-correct scoring procedure; the k out of n reliability of a test, and an exact test for random guessing; "determining the length of multiple choice criterion-referenced tests when an answer-until-correct scoring procedure is used"; "a closed sequential procedure for comparing the binomial distribution to a standard"; "a closed sequential procedure for answer-until-correct tests"; "approximating the probability of identifying the most effective treatment for the case of normal distributions having unknown and unequal variances"; estimating the reliability of a mastery test with the beta-binomial model; "analyzing the distractors of multiple choice test items or partitioning multinomial cell probabilities with respect to a standard"; "solving measurement problems with an answer-until-correct procedure"; and "a polarization test for making inferences about the entropy of multiple-choice test items." (Author/BW)