A year after the shooting at Marjory Stoneman Douglas High School in Parkland, Florida, shook America, gun violence prevention has returned to the forefront of lawmaker conversations.
On the policy side, just last week, the House of Representatives passed legislation relating to gun background checks, specifically aimed at extending the background check review period from three days to 10 days.
On Thursday, the focus for lawmakers at a congressional hearing is gun violence research. As rates of gun deaths appear to be rising, the issue has been called a public health emergency.
The House Appropriations Committee's Labor, Health and Human Services, Education, and Related Agencies Appropriations Subcommittee is holding the hearing to address potential federal funding for gun violence prevention research as Congress enters the 2020 fiscal year appropriations process.
The idea is that more research could help better inform the nation's understanding of gun violence as well as the decision-making around possible legislation.
"Nearly 40,000 Americans are killed by guns each year, and tens of thousands more are treated for gun injuries," New York Congresswoman Nita Lowey, who chairs the House Appropriations Committee, said in a news release ahead of the hearing.
"It is clear that the United States faces a public health emergency of gun violence, one that is breaking apart families, eroding the safety of communities, and threatening our shared future," she said. "Only by conducting scientific research on gun violence can we better understand the causes of this crisis and develop and implement a public health response to reduce gun injuries and deaths."
Lowey said that without dedicated funding from Congress, the US Centers for Disease Control and Prevention "cannot move forward with the important work of performing research into the causes of gun violence."
The American College of Surgeons "supports an appropriations request of $50 million specifically for firearm morbidity and mortality prevention research through the CDC" as part of the 2020 fiscal year, Dr. Ronald Stewart, director of trauma programs at the American College of Surgeons Committee on Trauma, said in a prepared statement for delivery to lawmakers at the hearing.
Why a debate over funding gun violence research rages on
Thursday's hearing comes almost a year after Republican members of the House Appropriations Committee blocked a proposal to designate $10 million in funding for gun violence research. The vote against the proposal was 32-20.
Ahead of that vote, Democrats pushed for federal government funding to conduct gun violence research. Republicans argued that such research was never prevented in the first place. The Dickey Amendment, named after the late Republican Rep. Jay Dickey of Arkansas, sits at the heart of that tension.
The amendment passed in 1996 when Congress removed $2.6 million -- which is the amount the CDC spent on gun research during the prior year -- from the CDC's budget for fiscal year 1997. The amendment stated that "none of the funds made available for injury prevention and control at the Centers for Disease Control and Prevention may be used to advocate or promote gun control."
While this language does not explicitly ban research on gun violence, the CDC's previous investment of $2.6 million into firearm injury research was redistributed to study traumatic brain injury prevention.
So while the CDC commonly shifts budget priorities, ever since the mid-1990s, some scientists saw the Dickey Amendment as a way to "silence" the science of gun research.
More recently, amid a wave of mass shootings over the past decade, Democrats have been calling for a full repeal of the Dickey Amendment to give a clear go-ahead to the CDC to resume research.
The National Rifle Association has long supported the amendment.
"The Dickey Amendment has never restricted the Centers for Disease Control and Prevention from studying firearms and violence. Instead, it restricts government funding from being used to advocate or promote gun control," the NRA said in a public post on Twitter last year.
Funding for studies on gun violence also may come through other routes, for example from foundations or the National Institute of Justice, but some researchers say that's not enough.
What's left to learn in gun violence data
Access to data from crime gun traces conducted by the Bureau of Alcohol, Tobacco, Firearms, and Explosives can give researchers insight into the perpetrators and policies that may play a factor in gun violence, according to prepared remarks by Daniel Webster, a professor and director of the Center for Gun Policy and Research at the Johns Hopkins Bloomberg School of Public Health in Baltimore, submitted in advance of his testimony at Thursday's hearing.
Such data can "indicate whether each criminal gun possessor was the legal purchaser of the firearm involved in crime, whether the purchaser of the gun that was later used in crime purchased other guns involved in crime, or how crime guns that are diverted for criminal use shortly after a retail sale are distributed across retail gun sellers within an area," he said in the prepared remarks.
Compared with research on other leading causes of death, research on gun violence has been associated with less funding and fewer publications, according to a paper published in the medical journal JAMA in 2017.
The paper involved analyzing data on research funding from 2004 to 2015, and correlating that data with mortality statistics from the CDC from 2004 to 2014.
The paper found that gun violence research had about $22 million or 1.6% of the $1.4 billion in funding that was predicted based on the mortality rate associated with gun violence. Gun violence also made up 4.5% of the volume of research publications that were predicted, the paper showed.
"Gun violence killed about as many individuals as sepsis. However, funding for gun violence research was about 0.7% of that for sepsis and publication volume about 4%," the researchers wrote in that paper. "In relation to mortality rates, gun violence research was the least-researched cause of death and the second-least funded cause of death after falls."
In prepared remarks shared ahead his testimony, economist John Lott, president of the Crime Prevention Research Center and author of "The War on Guns," said people have been misled "into thinking that gun violence has been understudied." He said public health research can be "poorly done" and "misleading," and can exclude research by economists, criminologists and law professors.
"The money spent is likely to be counterproductive to saving lives. If there are too few resources being devoted to firearms research, it lies in areas outside of Public Health. Any government funded research must strive to obtain quality research that will actually help save lives," Lott's prepared remarks said.
"I'd want to see renewed interest and many more resources devoted to the scientific study and prevention of gun violence," said Charles Branas, professor and chair of the department of epidemiology at Columbia University's Mailman School of Public Health in New York, who was senior author of a gun violence study published in the medical journal The BMJ on Wednesday.
The study found that states with more permissive gun laws had higher rates of mass shootings compared with states with more restrictive laws. Also, a growing divide in mass shooting rates appears to be emerging between those restrictive and permissive states, according to the study.
"More specifically, the rate of mass shootings in permissive states appears to be increasing since 2010, while the rate in restrictive states appears to be decreasing," said Branas, the study's senior author.
"We were somewhat surprised most by the recent, growing divergence in the rates of mass shootings between permissive and restrictive states," he said.
The study involved data from the Federal Bureau of Investigation's Uniform Crime Reporting System. That data, from 1998 to 2015, was used to calculate mass shooting rates in each state. A mass shooting was defined as an incident in which four or more people were killed by a firearm.
The researchers also developed an annual scale of how restrictive or permissive gun laws were in each state, based on the 1998-2015 edition of "Traveler's Guide to the Firearms Laws of the Fifty States," a report published by legal professionals for gun owners who travel between states.
Scores on that scale were given to each state depending on how restrictive or permissive their gun laws were based on various factors, such as requirements around permits and standard firearms ownership or whether semi-automatic, high-capacity magazines, machine guns, or suppressors were permitted or restricted in a state.
The study found that a 10-unit increase in a state's gun law permissiveness score was associated with an 11.5% higher rate of mass shootings, and a 10% increase in state gun ownership was associated with a 35.1% higher rate of mass shootings.
The study had some limitations, including that the findings were associations and not evidence of causation.
"It's hard to be 100% certain that what we found isn't possibly because states that experience more mass shootings in turn changed their gun laws, or some other factors that we just couldn't measure," Branas said.
Additionally, there are concerns about potential under-reporting of data in the Uniform Crime Reporting System, and the study only looked at mass shootings, not shootings involved in other crimes or overall crime rates.
All in all, Branas said, "For mass shootings, we'd love to see more of a call for better data collection on these tragedies and funding for new scientific study of which specific laws are accounting for the differences between permissive and restrictive states that we are just now finding."