In October 2015, Katherine Moussouris and Holly Muenchow filed as named plaintiffs for certification for a class action to the United States District Court, Washington, to cover 8600 female engineers and IT professionals who had worked at Microsoft Corporation since 2012. Their allegations concerned a purported “continuing policy, pattern and practice of sex discrimination against female employees in technical and engineering roles, including technical sales and services positions, with respect to performance evaluations, pay, promotions, and other terms and conditions of employment”. The human resource management practices of Microsoft, as implemented through its performance and reward management system, the “Calibration Process” (since 2014 “People Discussions”) were central to these claims. This system in both forms was alleged to systematically produce bias through a disparate impact on female employees, with further allegations that Microsoft negatively engages in disparate treatment through a general policy of intentional discrimination (Box 24.1). Further allegations were raised regarding the handling of sexual harassment cases and an “unchecked gender bias that pervades its corporate culture.