Legalized sports betting comes with a hidden public safety cost: a measurable rise in violent and impulsive crime on game days––even in states without gambling, according to new research led by the University of Michigan.
Researchers from U-M and Rice University analyzed crime incident data from 2017 to 2021 and found that states that legalized sports betting after the 2018 Supreme Court decision in Murphy v. NCAA saw significant increases in assaults, larceny and vehicle theft during and immediately following professional sports games. Crime levels rose the most when betting outcomes defied expectations––for instance, when underdogs won.
"There is a sizable increase in crime on game days associated with sports betting, both in states that legalized sports betting and in bordering areas of neighboring states where sports betting remains illegal," said Wenche Wang, who led the research while an assistant professor of kinesiology at U-M and who now works in a state government agency that oversees the energy sector.
Wang and co-author Hua Gong, assistant professor of sport analytics at Rice, say that legalized sports betting is lucrative for states.
"Sports gambling is exciting for fans and financially attractive for states, but our findings show it can also lead to more crime," Gong said. "When people lose their bets or go through very stressful game moments, that emotional volatility can translate into aggressive behavior."
The researchers say the pressing concern for states like Michigan with a mature, online legalized betting culture is that the dominant driver of betting-related crimes appears to be shifting to nonfinancial-related sources, particularly the stressfulness of the game itself, as bettors increasingly wager on more unpredictable contests.
"This introduces an additional challenge for public health experts seeking to mitigate the negative impacts of betting," Wang said.
Key findings:
Crime increases 30%-70% from the start of a game through four hours after its conclusion in states that legalized sports betting, with the largest increases tied to home games and unexpected outcomes.
Assaults see the largest jump—up to 93% after unexpected home team outcomes.
Spillover effects appear in neighboring states even when those states have not legalized betting.
"It is also worth noting that aggression may not stem solely from financial stress, as often observed in other forms of betting," Wang said. "We find recent evidence of increased crime associated with stressful games, such as those with close or tied scores throughout, as well as games that extend into overtime."
This could mean more risk in states with legalized betting.
"Shifts in bettor behavior suggest that legalized areas may be even more vulnerable to heightened aggressive behavior as even games where bettors incur no financial loss could be associated with increased crime," Wang said.
Sports betting is now legal in 38 states plus Washington, D.C., and Puerto Rico, and generates billions in tax revenue. But Gong says policymakers need to understand the tradeoffs.
"Legal betting brings in revenue, but there are serious social consequences we cannot ignore," he said. "Lawmakers should consider safeguards, better consumer protections and public awareness efforts as the industry continues to expand."
The study appears in the Journal of Sports Economics.
Study: The Impact of Legalized Sports Betting on Aggression (DOI: 10.1177/15270025251396530)
By Kat Cosley Trigg of Rice University
