<P> In the United States, research into firearms and violent crime is fraught with difficulties, associated with limited data on gun ownership and use, firearms markets, and aggregation of crime data . Research studies into gun violence have primarily taken one of two approaches: case - control studies and social ecology . Gun ownership is usually determined through surveys, proxy variables, and sometimes with production and import figures . In statistical analysis of homicides and other types of crime which are rare events, these data tend to have poisson distributions, which also presents methodological challenges to researchers . With data aggregation, it is difficult to make inferences about individual behavior . This problem, known as ecological fallacy, is not always handled properly by researchers; this leads some to jump to conclusions that their data do not necessarily support . </P> <P> In 1996 the NRA lobbied Congressman Jay Dickey (R - Ark .) to include budget provisions that prohibited the Centers for Disease Control (CDC) from advocating or promoting gun control and that deleted $2.6 million from the CDC budget, the exact amount the CDC had spent on firearms research the previous year . The ban was later extended to all research funded by the Department of Health and Human Services (DHHS). According to an article in Nature, this made gun research more difficult, reduced the number of studies, and discouraged researchers from even talking about gun violence at medical and scientific conferences . In 2013, after the December 2012 Sandy Hook Elementary School shooting, President Barack Obama ordered the CDC to resume funding research on gun violence and prevention, and put $10 million in the 2014 budget request for it . Prior to this, U.S. public funding directed towards gun violence prevention was less than $2 million annually, a disproportionately low total compared to public funding totals for other leading public health burdens with respect to potential years of life lost . </P>

Number of gun deaths in the us each year