The cognitive ability levels of different ethnic groups have interested psychologists for over a century. Many narrative reviews of the empirical literature in the area focus on the Black-White differences, and the reviews conclude that the mean difference in cognitive ability (g) is approximately 1 standard deviation; that is, the generally accepted effect size is about 1.0. We conduct a meta-analytic review that suggests that the one standard deviation effect size accurately summarizes Black-White differences for college application tests (e.g., SAT) and overall analyses of tests of g for job applicants in corporate settings. However, the 1 standard deviation summary of group differences fails to capture many of the complexities in estimating ethnic group differences in employment settings. For example, our results indicate that job complexity, the use of within job versus across job study design, focus on applicant versus incumbent samples, and the exact construct of interest are important moderators of standardized group differences. In many instances, standardized group differences are less than 1 standard deviation. We conduct similar analyses for Hispanics, when possible, and note that Hispanic-White differences are somewhat less than Black-White differences.