At American schools with powerhouse football programs, college game day often brings hordes of rowdy visitors and booze-soaked tailgates. Students wake early and chug vodka with breakfast. Gift shops sell T-shirts that brag, “Never lost a party.”

Jason Lindo, an economic professor at Texas A&M University, wondered if this elevated revelry intensified the risk of sexual assault on campus. Alcohol, he knew, promotes aggression.

So, Lindo and his colleagues analyzed 22 years of FBI data to compare reports of rape to the law enforcement agencies serving students at Division 1 schools on game days to reports on non-game days, controlling for differences expected across different days of the week and times of the year.

They found a strong link between football match-ups and an increase in college women, ages 17 to 24, reporting rape. Such reports increased on the days of home games by 41 percent, according to a new study, published Monday. They spiked 15 percent during away games.

And after underdog teams unexpectedly beat higher-ranked opponents on campus, reported rapes on average surged a whopping 57 percent.

Overall, researchers conclude, football games are associated with 253 to 770 additional rapes per year across the 128 schools in Division 1A.

“Potential perpetrators,” the authors wrote, “may believe that the probability of being punished (and the degree of punishment) will be lower if they and/or their victims are inebriated.”

Campus rape remains prevalent. Earlier this year, an Association of American Universities survey of 150,000 students at 27 universities found that, since enrolling in college, 13.5 percent of senior undergraduate women and 2.9 percent of senior undergraduate men had experienced “non consensual penetration involving physical force or incapacitation."

Lindo’s team didn’t intend to single out football as a primary driver of campus rape. They wanted to investigate the connection between traditionally boozy events and crime rates.

Touchdowns probably don’t trigger more assaults. Though causation cannot be proved, he said, the game day increase is likely related to an increased consumption of alcohol. The crime data showed arrests on home game days increased 54 percent for disorderly conduct, 20 percent for DUIs and 87 percent for public intoxication.

Most survivors in Lindo’s sample told authorities they were assaulted by someone they didn’t know.

Earlier this year, a Washington Post-Kaiser Family Foundation survey found that 77 percent of students said reducing drinking on campus would be effective in the fight to prevent sexual assault.

Beyond urging students to cut down on their alcohol intake, Lindo argues schools should ramp up policing efforts on game days and invest more resources in rape prevention programs that teach young adults about consent, for example, and why bystanders should swiftly intervene to stop possible assaults.

The authors put a price tag on the sexual assaults surges, using figures from a 2010 study on the economic losses associated with crimes, tangible (medical care, therapy, costs throughout the criminal justice system) and intangible (mental anguish, stigma).

Each rape, they wrote, carries a social cost of $267,000: “This implies an annual social cost of rapes caused by Division 1A games between $68 million and $205 million.”

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