The standardization approach to assessing differential item functioning (DIF), including standardized distractor analysis, is described. The results of studies conducted on Asian, Hispanic (Mexican American and Puerto Rican), and Black Americans on the Scholastic Aptitude Test are described and then synthesized across studies. Where the groups were limited to include only examinees who spoke English as their best language, very few items across forms and ethnic groups exhibited large DIF. Major findings include evidence of differential speededness for Blacks and Hispanics, and when the item content is of special interest, advantages for the relevant ethnic group. In addition, homographs tend to disadvantage all three ethnic groups, but the effect of vertical relationships is not as consistent. Although these findings are important in understanding DIF, they do not seem to account for all differences. Other variables related to DIF still need to be identified. Furthermore, these findings are seen as tentative until corroborated by studies using controlled data collection designs.