The standard error of measurement (SEM) is a measure of the inconsistency in the scores of a particular group of test-takers. It is largest for test-takers with scores ranging in the 50 percent correct bracket; with nearly perfect scores, it is smaller. On tests used to make pass/fail decisions, the test-takers' scores tend to cluster in the range…

In mastery testing a linear relationship between an optimal passing score and test length is presented with a new optimization criterion. The usual indifference zone approach, a binomial error model, decision errors, and corrections for guessing are discussed. Related results in sequential testing and the latent class approach are included. (CM)

The standard error of measurement usefully provides confidence limits for scores in a given test, but is it possible to quantify the reliability of a test with just a single number that allows comparison of tests of different format? Reliability coefficients do not do this, being dependent on the spread of examinee attainment. Better in this…