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A new study finds no evidence of a widespread surge in total, violent or property crime in large U.S. cities in the aftermath of the highly publicized police shooting of Michael Brown. But the research does show the overall rate of robberies across the country has increased, as has the murder rate in certain cities.

The study – the most comprehensive of its kind to date – tests the hypothesis that the shooting of Brown, a young black man, by a white police officer in Ferguson, Missouri – and a string of similar incidents across the country – have led to increases in crime across the U.S., a phenomenon known as the “Ferguson effect.” Researchers analyzed monthly crime data from 81 large U.S. cities the year before and year after the events in Ferguson on Aug. 9, 2014. The results were published today online in the Journal of Criminal Justice.

"The finding that crime rates are essentially unchanged means that a ‘Ferguson effect’ cannot be singled out as the driving factor of any widespread increase in crime other than robbery.”

“We have seen crime rates drop to historic lows over the last two decades so any potential increase in crime, especially violent crime, is of great concern,” said lead study author David Pyrooz, an assistant professor of sociology at the ��ƷSM����ӰƬ. “However, the finding that crime rates are essentially unchanged means that a ‘Ferguson effect’ cannot be singled out as the driving factor of any widespread increase in crime other than robbery.”

The high-profile shooting took social media by storm and has fueled ongoing national discussions about policing in cities across the nation. Pyrooz said the national discourse surrounding the so-called “Ferguson effect” as the cause of an upswing in crime rates has been “long on anecdotes and short on data.”

“The one crime that is showing signs of increasing is robbery,” said study co-author Scott Decker, foundation professor of criminology and criminal justice at Arizona State University. “Robbery drives fear of crime among the general population and is among the most feared crimes, so that’s concerning.”

Another concerning finding is the increase in homicide rates in select American cities. Pyrooz said cities with increases in homicide after the Ferguson shooting shared certain characteristics.

“These are cities with historically high levels of violence, high concentrations of socioeconomic disadvantages, more police per capita and a demographic makeup that differs from cities where homicide rates remained flat,” said Pyrooz.

For the study, researchers gathered monthly crime data from police departments and websites in cities with populations of at least 200,000. Offenses reviewed included homicide, forcible rape, robbery, aggravated assault, burglary, larceny-theft and motor vehicle theft. These are the offenses used by the FBI in measuring serious crime in the U.S.

Some law enforcement, criminal justice experts, commentators and policymakers have raised concern that rampant social media sharing of messages critical of law enforcement amplified the effect of the Ferguson shooting.

Specifically, some have argued that social media sharing caused police not to intervene in certain criminal settings for fear of criticism or lawsuits and also led to a widespread mistrust of police. However, the finding that crime rates are not significantly higher since Ferguson means that these factors are not causing an increase in crime, the researchers said.

“What we do know is that if de-policing or a legitimacy crisis is occurring, neither is impacting crime rates systematically across large U.S. cities,” said co-author Scott Wolfe, assistant professor in the department of criminology and criminal justice at the University of South Carolina. “Future research should examine these issues since they are critical to the effective administration of justice in the U.S.”

John Shjarback of the department of criminal justice at the University of Texas at El Paso also contributed to the study.

Julie Poppen is a senior news editor for the .