Newswise — College football games are linked to aggressive behavior, according to a new study by Daniel I. Rees, PhD, associate professor of economics at the University of Colorado Denver, and Kevin T. Schnepel, a graduate student in the economics program at UC Denver.

The study spans six football seasons from 2000 to 2005 and examines daily offense data from 26 police agencies, each located in communities where a Division I-A college football team played its home games. The goal was to find out if assaults and other offenses such as vandalism departed from normal patterns on game days. Specifically, Rees and Schnepel examined changes in the number of offenses reported by a police agency when the football program located in the community under its jurisdiction played a home game and the change in offenses when the program played an away game. In addition, they investigated whether the outcome of the game affected the relationship between game days and offenses.

"Results suggest that the host community, on average, experiences a nine percent increase in assaults on game days," said Rees. "In addition, there is evidence that vandalism, arrests for disorderly conduct and alcohol-related arrests increase on game days, but there is no support for the hypothesis that away games are related to offenses."

Specifically, home games are associated with a 9 percent increase in assaults, an 18 percent increase in vandalism, a 13 percent increase in arrests for drunk driving, a 41 percent increase in arrests for disorderly conduct, and a 76 percent increase in arrests for liquor law violations.

The largest estimated effects are found when an upset occurs, defined as when an unranked team beats a ranked team or when a lower-ranked team beats a higher-ranked team. In fact, the estimates suggest that assaults increase by 112 percent with an upset loss at home and by 36 percent with an upset victory. For the typical police agency, this would translate into an additional 6.7 reports of assault in the case of an upset loss on a Saturday and an additional 2.2 reports of assault in the case of an upset win.

"To date, no empirical study has attempted to document the magnitude of this phenomenon," said Rees. "Our results suggest that the host community registers sharp increases in assaults, vandalism, arrests for disorderly conduct and arrests for alcohol-related offenses on game days. Upsets are associated with the largest increases in the number of expected offenses."

Some portion of the relationship between home games and offenses may be mechanical in nature, due to the fact that home games often attract a temporary, but substantial, influx of people from outside the host community. However, the results with regard to upsets suggest that fans are reacting to the outcome of games.

Rees says that although there is evidence that upset losses are associated with a larger increase in assaults than are upset wins, the results clearly indicate that expectations, and what happens to fans' behavior when they are not met, must be built into future attempts to model the relationship between aggression and sporting events.

The University of Colorado Denver is one of three universities in the University of Colorado system. Located in Denver on the Downtown Campus and at Ninth & Colorado Blvd., and on the Anschutz Medical Campus in Aurora, Colo., University of Colorado Denver is Colorado's premier research university offering more than 100 degrees and programs in 13 schools and colleges and serving more than 28,000 students in Metro Denver and online.