THE ISSUE OF ITEM AND TEST VARIANCE FOR CRITERION‐REFERENCED TESTS1

It has been argued that item variance and test variance are not necessary characteristics for criterion-referenced tests, although they are necessary for normreferenced tests. This position is in error because it considers sample statistics as the criteria for evaluating items and tests. Within a particular sample, an item or test may have no variance, but in the population of observations for which the test was designed, calibrated, and evaluated, both items and tests must have variance.