Quartz: “There are gender pay gaps … and then there are median gender pay gaps. Understanding the difference between the two may determine just how much progress women make in terms of fairer compensation in the next decade. So first, the definitions: “Equal pay” gap: What women are paid versus their direct male peers, statistically adjusted for factors such as job, seniority, and geography. Often referred to in the context of “equal pay for equal work.” “Median pay” gap:  The median pay of women working full time versus men working full time. This is an unadjusted raw measure used by the Organization for Economic Cooperation and Development (OECD).  Women in the US, for example, make 80 cents on the dollar versus men on this basis.

Equal pay gaps measure whether women are being paid commensurate with their peers for the work they are doing today. But median pay gaps measure whether or not women are holding as many high-paying jobs as men. Narrowing the median pay gap means putting more women in leadership (and reaping the performance benefits that diversity affords). And that’s where investors come in. Concerned shareholders in major US financial and tech companies want to make sure the pay gap difference is understood—and acted upon. Consider the case of Citigroup. While it is true that women at Citi are paid 99% of what men are paid on an equal-pay basis when adjusting for job function, level, and geography, the median pay gap at the financial giant paints a very different picture: Women at Citigroup earn just 71% of what the men earn…”