Aileen Rizo, who is an employee of the public schools in Fresno County, sued for violation of the federal Equal Pay Act (“EPA”) after she learned that her male counterparts were being paid more for performing the same work. In its summary judgment motion, the county argued that it paid males more than females based upon a factor other than sex, namely the higher salaries that male employees earned before being employed by the county. The district court rejected that argument and held that when an employer bases a pay structure “exclusively on prior wages,” any resulting pay differential between men and women is not based on a factor other than sex. However, the United States Court of Appeals for the Ninth Circuit vacated and remanded the judgment, holding that if the employer is able to show that prior salary “effectuates some business policy” and the employer uses prior salary “reasonably in light of its stated purpose,” prior salary can be a factor other than sex, resulting in no liability under the EPA. Compare Cal. Lab. Code § 1197.5(b)(3) (prohibiting reliance on prior salary by itself to justify any disparity in compensation).