A recent study found that male Uber drivers earn roughly 7% more per hour than women on average. Researchers ascribed the gender pay gap to male drivers being more risk tolerant, working in areas that were more lucrative and driving faster.

Researchers from Stanford University and the University of Chicago looked at Uber data of around 120,000 drivers from January 2015 to March 2017 and measured how much they were paid per hour, focusing their attention on drivers in Chicago. During that period, 30% of the drivers were female and 33 million driver hours were logged.

Stanford professor Rebecca Diamond, one of the study’s authors, asserted that the data allowed for a unique look at gender payment disparity on a particular job.

“We’re the first study to fully unpack the gender pay gap,” Diamond told Yahoo Finance. “Uber is really in this nice situation that they have all this detailed data … and we could quantify them in a very clean way.”

The study, which was first published in February as a working paper, is now published on the National Bureau of Economic Research (NBER) website.

‘Areas with higher crime and more drinking establishments’

One factor contributing to men earning more was risk tolerance.

Men drove 2.2% faster than women, according to the study, which the researchers claimed explained half of the earnings gap.

The study also found that 20% of the gender wage gap “can be attributed to differences in where male and female Uber drivers live.” Men tended to drive in “more lucrative locations,” as well as in “areas with higher crime and more drinking establishments.”

Women, meanwhile, consciously avoided “areas with a higher incidence of crime or where there is a higher likelihood of picking up intoxicated passengers,” which affected their “ability to earn money on Uber.” Men also drove “more during the late-night hours, while women drive substantially more on Saturday and Sunday afternoon.”