(CN) – New research reveals that, on average, cities experienced 2.3 more assaults on days when they hosted rallies for then-candidate Donald Trump during the 2016 presidential election campaign.
In the study, published Friday in the journal Epidemiology, researchers from George Mason University and the Perelman School of Medicine at the University of Pennsylvania also found no link between Hillary Clinton rallies and spikes in assaults.
“News media sources reported there were violent incidents at some campaign rallies, but it was difficult to gauge whether there really was a systematic problem, and if so, how many additional assaults were associated with each rally,” said lead author Christopher Morrison, a fellow in Penn’s Center for Clinical Epidemiology and Biostatistics.
“To prevent similar violence in the future, it is important to understand the underlying causes of this behavior, perhaps including the role that political rhetoric might play in normalizing or promoting violence.”
The team focused on cities with more than 200,000 people and performed a systematic Google search that revealed publicly available data for 38 rallies in 21 cities for Clinton, and 31 rallies in 22 cities for Trump. Using aggravated assault, simple assault, and battery data from police departments in those cities, they then tallied assaults on corresponding days of the week for four weeks before and after each rally.
Their report defined rallies as open-invitation events that occurred after Clinton and Trump declared their candidacies in the spring of 2015 and before the election on Nov. 8, 2016, that featured a speech by either candidate, and were not on the same day as a party primary election in the same state as the event.
The authors offer two possible explanations for their results.
First, all additional assaults could have occurred in and around Trump’s rally venues. This explanation backs up news reports that violence broke out at these specific locations.
Second, additional assaults might have occurred in other parts of the rally cities. Research informed by theories of social cognition have found evidence that emotional dispositions can be transmitted through digital social media and news reports, which could have led to more assaults taking place away from the rally sites.
The team notes Trump rallies were widely broadcast, covered in news reports, and discussed on social media. One such rally occurred in Cedar Rapids, Iowa, during which the future president said he would “knock the crap out of” would-be hecklers at the event, and other examples have been documented by the nonpartisan website PolitiFact.
“This research provides evidence that this increase in assaults is associated with candidate Trump’s rallies leading up to the election,” said senior author Douglas Wiebe, an associate professor of epidemiology at Penn. “Violent language may have affected the mood and behavior of rally attendees, as well as those exposed to the rally through news reports and social media.”
The authors also noted that weather can impact crime rates, so they used National Oceanic and Atmospheric Administration data for the weather station closest to each study city to control for precipitation and temperature.