As for cultural bias:  https://lesacreduprintemps19.files.wordpress.com/2012/11/the-bell-curve.pdf Are the Differences in Black and White Scores Attributable to Cultural Bias or Other Artifacts of the Test? Appendix 5 contains a discussion of the state of knowledge regarding test bias. Here, we shall quickly review the basic findings regarding blacks, without repeating the citations in Appendix 5, which we urge you to read. EXTERNAL EVIDENCE OF BIAS. Tests are used to predict things-most commonly, to predict performance in school or on the job. Chapter 3 it has a certain validity in predicting college performance. If the SAT is biased against blacks, it will under predict their college performance. If tests were biased in this way, blacks as a group would do better in college than the admissions office expected based just on their SATs. It would be as if the test underestimated the "true" SAT score of the blacks, so the natural remedy for this kind of bias would be to compensate the black applicants by, for example, adding the appropriate number of points onto their scores.  Predictive bias can work in another way, as when the test is simply less reliable-that is, less accurate-for blacks than for whites. Suppose a test used to select police sergeants is more accurate in predicting the performance of white candidates who become sergeants than in predicting the performance of black sergeants. It doesn't under predict for blacks, but rather fails to predict at all (or predicts less accurately). In these cases, the natural remedy would be to give less weight to the test scores of blacks than to those of whites. The key concept for both types of bias is the same: A test biased against blacks does not predict black performance in the real world in the same way that it predicts white performance in the real world. The evidence of bias is external in the sense that it shows up in differing validities for blacks and whites. External evidence of bias has been sought in hundreds of studies. It has been evaluated relative to performance in elementary school, in secondary school, in the university, in the armed forces, in unskilled and skilled jobs, in the professions. Overwhelmingly, the evidence is that the major standardized tests used to help make school and job decision~'~~~ do not under predict black performance, nor does the expert community find any other general or systematic difference in the predictive accuracy of tests for blacks and whites.