"Outlier studies" identify items for which extreme differences in performance by contrasting groups occur; these extreme items are the "outliers" referred to. Review of the studies conducted on tests receiving major use in higher education reveals that though one cannot make a priori classifications of outliers with confidence, one can with reasonable confidence predict the relatively advantaged group for many verbal items if they subsequently prove to be outliers as follows: aesthetic-philosophical, human relations or female oriented content relatively favors females as opposed to males; practical affairs, science or male oriented content relatively favors males as opposed to females; science content relatively favors whites as opposed to blacks. For test content that varies in the degree of relatedness to minorities, one would predict a relative advantage for those outliers that are most related to minorities. The magnitude of the differences found is not large; perhaps larger differences would be found if classifications other than race and sex, which are the most common, were used. It has been found that differences in cultural or national origin produce larger discrepancies in item difficulty than differences in race or sex of essentially native American groups. (Author)