Significantly less crime is reported around baseball stadiums when fans have time to sober up after alcohol sales are stopped at the end of the seventh inning, according to new work by researchers who used nearly a decade of data from Philadelphia.

In a paper for the Journal of Quantitative Criminology, researchers said that the alcohol cut-off policy led to a small but statistically significant overall drop in crime; the number of assaults dropped the most dramatically, falling by 40% to 70%. 

"What we find is that crime in general goes down when games run long," said co-author and University of Pennsylvania criminology and sociology professor John MacDonald in an interview with The Academic Times. "Assaults are still thankfully rare on any given day, but it's still suggesting you're getting maybe an additional one or two assaults that occur on a game day because of the alcohol sales." 

The effect on crime could also extend to other sports games and to other events like concerts and music festivals, according to MacDonald. 

"Anytime you have alcohol sales in mass gatherings there's this potential for social interactions to go differently," he said. 

But while the pattern may be observed at other mass gatherings, Major League Baseball games provide a unique opportunity to examine the effect of alcohol sales and drunkenness on crime due to their cut-off policies, MacDonald said. 

All MLB teams stop selling alcohol before the end of games, and the most common policy is to cut off sales at the end of the seventh out of nine innings. Since innings are based on the number of outs and therefore have no fixed duration, the amount of time between the cut-off for alcohol sales and the end of the game can vary dramatically. 

"There are games where you have your last beer at your seventh inning and then you watch for another two hours before you leave," said MacDonald, who wrote the paper alongside University of Pennsylvania law professor Jonathan Klick.  

In order to ensure that they were observing the effects of the sobering-up period on crime, MacDonald and Klick compared Philadelphia Police Department crime reports made between 2006 and 2015 from Citizens Bank Park, where the Philadelphia Phillies play, and sports bars around the city, where patrons can keep drinking throughout the game. Crime around the bars was not significantly affected by game length, the researchers found.

Another point of comparison came in 2012, when a complex of bars that served drinks after the seventh inning opened in the stadium's parking lot. Since game-goers were no longer forced to sober up before leaving the area, the new bars had the effect of eliminating the reduction in crime associated with the alcohol cut-off policy, including the estimated 40% to 70% reduction in assaults.  

MacDonald said he was surprised by the degree of alcohol sales' association with assaults, since MLB fans aren't known as a particularly violent bunch. 

"Baseball's not a sport where people go to the baseball stadium to get in a fist fight with rival fans," he said. 

MacDonald and Klick are not the first researchers to examine connections between sports stadiums and crime. A 2015 Statistics in Society paper by Maastricht University economist Olivier Marie associated a significant uptick in property crimes with soccer matches in London, but no notable effect on violent crime. And a 2011 study by Stephen Billings and Craig Depken II for the Springer book series Sports Economics, Management and Policy associated game days with increases in overall crime around two sports venues in Charlotte, North Carolina. Other researchers have studied changes in crime in the neighborhoods around stadiums.  

What makes the Phillies study unique is that the stadium's alcohol policy and the introduction of the parking lot sports bars allowed the researchers to better examine the causal effect of sports game alcohol consumption on crime, according to MacDonald and Klick. 

"Baseball is different from other sporting venues because of the seventh inning alcohol stoppage, and so we thought, 'There's an interesting natural experiment,'" said MacDonald. 

Developing the paper from idea to publication took about three years, MacDonald said. Obtaining crime data from the Philadelphia police was remarkably easy thanks to the department's crime statistics tool, but gathering nearly a decade of game-by-game data from the MLB was more difficult, according to MacDonald. 

The findings can help inform security planning for mass gatherings as COVID-19 restrictions are gradually lifted this year, MacDonald said; for example, event planners should perhaps consider cutting off alcohol sales earlier.

"Think about how you do queuing, how people are let out of stadiums during what period of time," MacDonald said. "If any kind of social event is going to pay for extra security, it might be more important to focus on that exiting time." 

The study, "Sobering Up After the Seventh Inning: Alcohol and Crime Around the Ballpark," published March 8 in the Journal of Quantitative Criminology, was authored by John MacDonald and Jonathan Klick of the University of Pennsylvania.