Microsoft systematically paid and promoted some female technical employees less than men, a report commissioned by the plaintiffs in a gender discrimination lawsuit against the company has found. The report, by Princeton economics professor Henry Farber, analyzed thousands of Microsoft employees’ pay and promotions over the course of four years and determined that certain female employees — those in low- to mid-level jobs — “received lower compensation on average than otherwise similar men,” and that mid-level female technical employees were also discriminated against with regard to promotions.

A second report, by Michigan State professor Ann Marie Ryan, found that Microsoft’s guidelines for advancement are not clear. When companies don’t make their promotion guidelines clear, it allows for decisions to be made more subjectively, which is often detrimental to women’s advancement prospects.

Both reports were submitted at the end of October as exhibits in the Microsoft gender discrimination class-action lawsuit, Moussouris v. Microsoft. The plaintiffs, who originally filed the lawsuit in 2015, filed for class certification on Oct. 27 of this year. The lawsuit alleges that Microsoft “has engaged in systemic and pervasive discrimination against female employees in technical and engineering roles … with respect to performance evaluations, pay, promotions, and other terms and conditions of employment.”

The suit goes on to say that “the unchecked gender bias that pervades Microsoft’s corporate culture has resulted in female technical professionals receiving less compensation than similar…