The WSJ reports on a study by Harvard economists, Valentin Bolotnyy and Natalia Emanuel, that finds an 11% gender pay gap—“60% of the earnings gap across the United States”— among union members of the Massachusetts Bay Transit Authority, despite rigorous seniority rules and guaranteed equal pay for equal work. The authors conclude: “The gap…can be explained entirely by the fact that, while having the same choice sets in the workplace, women and men make different choices. … Women value time and flexibility more than men.” Men worked 83% more overtime hours than women. They accepted twice as many last minute overtime shifts. And they worked more higher-paying nights, weekends, and holidays. Women took twice as much unpaid family leave. The authors note, “Since the operators at the MBTA are selected for their ability to work 24 hours a day, 7 days a week, it is likely that our estimate of the role of choice in the nationwide gender earnings gap is a lower bound.”
University of Michigan economist, Mark Perry, provides a more comprehensive list of the different choices made by men and women.
These findings align with those reached by Harvard economist, Claudia Goldin, who finds cumulative career hours worked accounts for the remaining gender pay gap beyond the lower-paying professions women tend to choose—e.g., social work versus computer programming.