Since its 2016 debut, Diversity Lab’s Mansfield Rule has become the most ubiquitous certification for a law firm’s commitment to transparent, diverse and equitable promotion and hiring practices. Despite getting more challenging to earn each year, certifications have grown from an initial 35-firm group in 2017 to 165 large law firms by 2022. With 78 Am Law 100 firms earning Mansfield Rule 5.0-certification in a Tuesday announcement, being Mansfield-certified is becoming an industry norm.

Yet, the nation’s largest and most profitable firms compose a majority of the Am Law 100 firms that don’t participate in the Mansfield Rule, which—among other factors—requires at least 30% representation of lawyers and staff from underrepresented groups in candidate pools for promotions, appointments, and lateral hiring for leadership roles.