Mass shootings may be ‘contagious’, according to US study

Mass shootings may be ‘contagious’, with one attack increasing the likelihood of another happening within the next fortnight, a US study has found.

“We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past,” the researchers found.

The “contagion period” of an attack lasts 13 days and increases the chance of another by a specific rate, the study found.

The study also found mass shootings – which kill four or more people – occur once a fortnight in the US, with school shootings occurring monthly.

Last month, data compiled by Reddit users found the US was averaging one mass shooting a day, with 295 mass shootings between January 1 and October 22.

A total of 357 people had died in the shootings.

Each state’s rate of firearm ownership is also apparently “significantly associated” with its incidence of mass shootings, the study found.

Two-thirds of school shooters used weapons from their family homes.

The study also references previous research that found firearm murder and suicides rates in the US are higher than those in all other industrialised nations.

The US rate of child deaths by firearms is five times higher than any other industrialised nation.

The study said a lack of legislation lifting a freeze on federal funding for gun violence research was hampering progress, with President Barack Obama’s calls for studies to be resumed failing to attract majority support.

Obama renewed his calls for action to prevent gun violence last month, after two fatal university shootings happened in 24 hours.

“We’re going to have to come together and figure out how to stop things like this from happening,” Mr Obama said.

“I’ve got some very strong feelings about this because when you talk to these families, you’re reminded that this could be happening to your child.”

His calls met with strong opposition in one of the university’s towns, with Oregon residents protesting against tighter firearm restrictions.

Presidential hopeful Hillary Clinton has also raised the issue of gun violence while on the campaign trail.

In October, she discussed Australia’s gun buyback model implemented by former Prime Minister John Howard after the Port Arthur Massacre.