The 1990s saw a dramatic drop in crime across the nation, but not in counties where Wal-Mart built new stores, according to a new study.

"The crime decline was stunted in counties where Wal-Mart expanded in the 1990s," said Scott Wolfe, assistant professor of criminology and criminal justice at the University of South Carolina and lead author of a new study. "If the corporation built a new store, there were 17 additional property crimes and 2 additional violent crimes for every 10,000 persons in a county."

Wolfe said the commonly known "Wal-Mart effect" is the company's overwhelming influence on numerous economic and social factors in communities, including jobs, poverty rates and retail prices.

"There have been dozens of studies on the 'Wal-Mart effect' showing the company impacts numerous outcomes closely related to crime. Our objective was to determine if the Wal-Mart effect extended to understanding crime rates during arguably one of the most pivotal historical periods in the study of crime," Wolfe said.

Wolfe and David Pyrooz, assistant professor of criminal justice and criminology at Sam Houston State University and co-author of the study, based their research on 3,109 US counties. The 1990s, the focus of their study, was a time of dynamic growth for the company and falling crime rates nationally. During that decade Wal-Mart expanded in 767 of those counties.

The researchers tracked crime rates in counties where Wal-Mart expanded and compared them to similar counties that Wal-Mart avoided.

"There is something unique about the counties that Wal-Mart selects," Wolfe said. "Wal-Mart tended to expand in counties with higher than average crime rates. These counties were more likely see Wal-Mart build even after accounting for crime-related predicators, such as poverty, unemployment, immigration, population structure and residential turnover."

The researchers speculate this relationship occurred because Wal-Mart finds it easier building in communities that are less likely to protest their arrival.

"Counties with more social capital-citizens able and willing to speak up about the best interests of the community-tend to have lower crime rates," Pyrooz said. "Counties with more crime may have less social capital and, therefore, less ability to prevent Wal-Mart from building."

Comparisons between Wal-Mart and non-Wal-Mart counties with similar crime rates and economic and demographic factors showed that the retailer's growth stunted what could have been greater drops in crime.

Wolfe and Pyrooz said the reason why Wal-Mart lessened a decline in crime is a complex question not easily answered by data typically available. Their findings didn't reveal that Wal-Mart's growth corresponded with increases in poverty, economic disadvantage or other factors associated with crime.

"More research is needed to uncover why the Wal-Mart effect extends to crime," Wolfe said. "Does it reduce community social cohesion or simply increase opportunities for theft and other crimes in specific store locations that are great enough to influence county crime rates? These are questions that remain."

Wolfe stresses that Wal-Mart is not uniformly detrimental. In fact, new Wal-Mart stores can be beneficial in some communities, particularly those in economic distress, he said.

"The problem, however, is that Wal-Mart is less likely to grow in communities with depressed economic conditions," Wolfe said.