In some societies, the law of equal opportunity forbids statistical discrimination when the basis of the discrimination is race or sex. The employer must base hiring and promotion decisions on facts about the individual applicants other than their being black or white, male or female, or the like (even if basing decisions on accurate stereotypes is the most cost-effective way to proceed). The rationale for this legal policy might be to ensure that historically invidious forms of discrimination are not continued by prohibiting forms of discrimination that are superficially similar and reminiscent of past evils. Formal equality of opportunity as characterized in this entry would not rationalize this legal policy.