During the past few years the problem of bias in testing has become an increasingly important issue. In most research, bias refers to the fair use of tests and has thus been defined in terms of an outside criterion measure of the performance being predicted by the test. Recently however, there has been growing interest in assessing bias when such criteria are not available. In test construction in particular, where criterion measures are usually not collected until after the test is completed, assessment of bias, in the absence of criteria has become a vital issue. If unbiased tests are to be built, it is important to identify potentially biased items during the construction process when test content is still flexible and items may still be modified or eliminated. Presented here are the author's research efforts over the past six years on bias in the construction of achievement tests. A general overview of the problem and some of the difficulties involved in studying it are also presented. (Author/DEP)