Game days at top US college football programs are associated with a significant rise in reports of rape from college-aged victims to law enforcement authorities, a new study has found.

The study, which examined the relationship between campus party culture and sexual assault, found “robust evidence” linking Division 1 football games to a 28% rise in reports of rape occurring the same day.

Home games drove the biggest bump, the authors found. In particular, reports of sexual assault by strangers grew 61% after home games. But upset losses and games against major rivals also drove a notable increase in rape reports coming from 17- to 24-year-olds.

Isaac Swensen of Montana State University, Jason Lindo of Texas A&M University, and Peter Siminski of Australia’s University of Wollongong co-authored the report, a working paper from the National Bureau of Economic Research. The authors say their findings support policies that rein in alcohol consumption at college parties. “By providing convincing evidence that spikes in the degree of partying at a university escalate the incidence of rape, our results suggest that efforts to avoid such spikes could serve to reduce the incidence of rape,” they wrote.

But the findings, are also likely to fuel an ongoing debate over whether “jock culture” is feeding a campus rape epidemic. In recent years, a parade of high-profile college football players and other athletes have been accused and convicted of sexual assault.

“Back-of-the-envelope” calculations led the authors to believe that Division 1 game days drive anywhere from 243 to 770 additional reports of rape at 128 schools. They caution, though, that they were limited to studying reports – not incidents – of rape, making their proportional findings much more valuable. The vast majority of victims do not report the crime to law enforcement, with some studies placing the reporting rate as low as 12%.