Disparate impact happens when an employer uses a facially neutral employment practice that has an adverse impact on members of a protected class. If the negative impact affects the protected group more harshly than the majority group, discrimination may be found. Practices that may be considered discriminatory are placement tests, aptitude tests, height and weight requirements or any other screening device that causes more than 20 percent of a protected group to fail the test. For example, 100 men and 100 women take an exam for a promotion. 90 of the women pass the test but only 45 of the men pass the test. The relevant ratio would be 45/90, or 50 percent, which would violate the 80 percent rule. Because the men did not pass at a rate of 80 percent of the women, the test is considered to have a disparate impact on men.
The plaintiff must prove, usually through statistical data, that the challenged practice has an adverse impact on a protected group.
The employer must prove that the challenged practice is a business necessity. Even if the employer proves business necessity, if an alternate employment practice that does not have the same effect on the minority group is available, the employer is still guilty of disparate impact. GRIGGS v. DUKE POWER CO., 401 U.S. 424 (1971) 401 U.S. 424 is the most famous court case dealing with disparate impact. Griggs was codified into law in 1991 through the Civil Rights Act of 1991.
In Griggs v. Duke Power Co. African American employees challenged Duke Power's policies requiring a high school diploma or passing of intelligence tests as a condition of employment in or transfer to jobs at the plant. These requirements went into effect right after the passage of Title VII. Before Title VII, all non-white...