complaint could amount to unlawful retaliation. This is all seen as necessary to make equal rights effective. Equal impact and remedies In addition to disparate treatment, employing entities may not use practices having an unjustified disparate impact on protected groups. In Griggs v Duke Power Co, a power company on the Dan River, North Carolina, required a high school diploma for staff to transfer to higher paying non-manual jobs. Because of racial segregation in states like North Carolina, fewer black employees than white employees had diplomas. The Court found a diploma was wholly unnecessary to perform the tasks in higher paying non-manual jobs. Burger CJ, for a unanimous Supreme Court, held the "Act proscribes not only overt discrimination, but also practices that are fair in form, but discriminatory in operation." An employer could show that a practice with disparate impact followed "business necessity" that was "related to job performance" but otherwise such practices would be prohibited. It is not necessary to show any intention to discriminate, just a discriminatory effect. Since amendments by the Civil Rights Act of 1991, if disparate impact is shown the law requires employers "to demonstrate that the challenged practice is job related for the position in question and consistent with business necessity" and that any non-discriminatory "alternative employment practice" is not feasible. On the other hand, in Ricci v DeStefano five Supreme Court judges held the City of New Haven had acted unlawfully by discarding test results for firefighters, which it concluded could have had an unjustified disparate impact by race. In a further concurrence, Scalia J said "resolution of this dispute merely postpones the evil day" when a disparate impact might be found unconstitutional, against the equal protection clause because, in his view, the lack of a good faith defense meant employers were compelled to do "racial decision making" that "is ... discriminatory." In dissent, Ginsburg J pointed out that disparate impact theory advances equality, and in no way requires behavior that is not geared to identifying people with skills necessary for jobs. Both disparate treatment and disparate impact claims may be brought by an individual, or if there is a "pattern or practice" by the Equal Employment Opportunity Commission, the Attorney General, and by class action. Under the Federal Rules of Civil Procedure, Rule 23 a class of people who share a common claim must be numerous, have "questions of law or fact