Gender representation on corporate boards of directors refers to the proportion of men and women who occupy board member positions. To measure gender diversity on corporate boards, studies often use the percentage of women holding corporate board seats and the percentage of companies with at least one woman on their board. Globally, men occupy more board seats than women. As of 2018, women held 20.8% of the board seats on Russell 1000 companies (up from 17.9% in 2015). Most percentages for gender representation on corporate boards refer only to public company boards. Private companies are not required to disclose information on their board of directors, so the data is less available.