In 2013, dozens of scholars organised by the Crime Lab of the University of Chicago released a letter calling for Congress to lift restrictions that have led the Centers for Disease Control and Prevention and other agencies to avoid funding research on gun violence.

The letter noted that in a 40-year period, the United States had experienced 400 cases of cholera and that the National Institutes of Health had funded 212 grants on cholera. The 1,337 cases of diphtheria had led to 56 NIH grants. But more than four?million firearms injuries? The NIH funded only three grants on that topic.

This week¡¯s horrific mass shooting in Las Vegas is once again prompting scholars ¨C particularly in social science groups ¨C to call?for shifts in federal policy to resume support for research on gun violence.

Felice Levine, executive director of the American Educational Research Association,??on Monday that said: ¡°In this period of human devastation and public pain, it is incumbent upon us to confront our collective responsibilities as researchers, educators and policymakers to engage in a dialogue about the pervasive and lethal effects of guns in the hands of those seeking to render violence.¡±

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Levine added, ¡°Once again, AERA calls on Congress to lift restrictions that prevent the Centers for Disease Control and Prevention from conducting gun violence research. These restrictions obstruct the development and implementation of evidence-based policies and programs that foster gun safety.¡±

The American Anthropological Association?, and social science groups have been issuing such statements for years. Here is?.

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The limits to which the statements refer were part of an appropriations bill enacted in 1996, provisions of which remain law. The key provision bars the CDC from using funds to support research that ¡°may be used to advocate or promote gun control.¡±

As reported by?, the CDC-backed studies that prompted the measure found that having guns increased the chances of violence in a home rather than providing protection. While scientists who conducted the research insisted that they were analysing data, the National Rifle Association attacked the research as advocacy for gun control. Republicans in Congress agreed.

In the years since 1996, Democrats in Congress have tried several times to have the limits lifted, but have been?.

In 2013, President Obama??and asked Congress for funds to do so. But with congressional Republicans making clear that they would interpret most such studies as violating the 1996 measure, the CDC has??at doing so. The NIH did start a program, but??reported last month that it had opted to let the programme end.

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Calls to change policy have typically followed mass shootings. President Obama¡¯s request followed the killings at Sandy Hook Elementary School. An unsuccessful Democratic congressional push on the issue followed the 2016 mass killing at an Orlando nightclub.

The lack of federal support for this research prompted the state of California?University of California, Davis, on the topic. The centre opened in June.

This is an edited version of a story that .