Griggs v. Duke Power Company was a landmark employment discrimination case decided by the U.S. Supreme Court in 1971. It concerned the legality, under Title VII of the Civil Rights Act of 1964, of high school diplomas and intelligence test scores as prerequisites for employment. The court ruled unanimously against the intelligence testing practices of the Duke Power Company. Chief Justice Warren Burger delivered the Court’s opinion that employers can use intelligence tests only if "they are demonstrably a reasonable measure of job performance."
The case originated in a lawsuit filed by Willie Griggs and twelve other African-American employees of Duke Power’s Dan River hydroelectric plant in Draper, North Carolina. Before the passage of the Civil Rights Act, Duke Power discriminated against African-Americans in hiring and promotion, restricting them to the company’s Labor department. In 1955, Duke Power instituted a high school diploma requirement for initial hiring in any department except Labor. (The other departments of Duke Power included Maintenance, Operations, and Laboratory.) In 1965, when the Civil Rights Act went into effect, this requirement was expanded to block transfers from Labor to other departments by employees who had not graduated high school.
Later that year, Duke Power began allowing non-high-school graduates to transfer from Labor to other departments if they could register sufficient scores on the Wonderlic Test, which rates general mental ability, and the Bennett Mechanical Comprehension Test, which is intended to predict job performance in mechanical fields. The scores that Duke Power required on each test were national median scores for high school graduates. The plaintiffs, Duke Power, and all courts that heard the case agreed that whites fared better than African-Americans on these intelligence tests. The tests thus put African-Americans at a disadvantage to whites in Duke Power’s hiring and advancement, and this disadvantage prompted the plaintiffs’ suit.
The plaintiffs’ argument was that Title VII of the Civil Rights Act, which forbade race-based discrimination in employment, prohibited employer-administered tests that could have an exclusionary effect African-Americans. A federal district court ruled in favor of Duke Power on the ground that Duke Power’s policy of overt racial discrimination – to wit, racial segregation – had ceased. After the case moved beyond the district level, the Fourth Circuit Court of Appeals ruled that the intelligence tests administered by Duke Power did not reflect any discriminatory intent and thus were not unlawful under Title VII of the Civil Rights Act.
The U.S. Supreme Court finally heard the case in late 1970, and Justice Burger’s opinion took several months to draft. The court overturned the rulings of the lower courts, deciding in favor of Griggs. Intelligence test scores and diplomas as requirements for employment, the court ruled, are not in themselves illegal under Title VII. Nevertheless, when diploma and test requirements (a) limit ethnic minority hiring and (b) do not pertain to job skills or performance, these requirements are illegal.
Speaking for the Court, Burger noted the fact that Duke Power made no serious effort to determine or demonstrate the effectiveness of diploma and intelligence test requirements as predictors of job performance. A vice president of the company had testified that Duke executives never compiled any evidence to justify the use of diploma and intelligence test requirements in hiring and advancement. According to the vice president’s testimony, these executives believed simply that these requirements would result in the hiring of better workers.
Despite Duke Power’s implementation of these requirements, none of the three federal courts that heard Griggs found that Duke Power had discriminatory intent. The Supreme Court ruled that Duke Power’s diploma and testing requirements were illegal because they had discriminatory consequences, founding a legal standard now known as "disparate impact." Before Griggs, employees or job applicants who accused employers of racial discrimination had to prove discriminatory intent to have success in litigation; after Griggs, those claiming discrimination had to prove only discriminatory effects of hiring or advancement practices.
After several court decisions undermined the disparate impact standard in the late 1980s, Congress passed the Civil Rights Act of 1991 to render the standard ironclad, renewing the influence of Griggs.