The other category consists of "disparate impact" cases, which do not require proof of intentional discrimination. Disparate impact doctrine proscribes facially neutral employment practices that have a disproportionately harsh effect on employees in protected classes, unless those practices are shown to be justified by business necessity. See Int'l Bhd. of Teamsters v. United States, 431 U.S. 324, 335 n.15 (1977). See generally Griggs v. Duke Power Co., 401 U.S. 424 (1971) (holding that the use of employment prerequisites that have an invidiously discriminatory impact, but are not related to job performance, can be prohibited even without a showing of intent).