If the federal government enacted just three gun-control laws—requiring universal background checks for firearms, background checks for ammunition, and firearm identification—gun deaths could fall by as much as 90 percent according to a new study.

The study, published in the The Lancet, tried to tease apart the independent effects that 25 state gun control laws implemented in various states in 2009 had on firearm related deaths (including homicides and suicides) between 2008 and 2010. The analysis, led by researchers at Boston University, also took into account factors related to gun deaths such as unemployment rates and levels of gun ownership.

However, some skeptics of the study wonder if the limited data of just a few years and correlations are enough to draw definitive links. The authors themselves admit that impacts of gun legislation could take several years to unfold in the statistics. And various other factors influencing gun death rates—such as suicide prevention efforts, law enforcement implementation, and demographics—may also skew the analysis.

“I'm generally skeptical of cross-sectional studies of association,” Garen Wintemute, an emergency physician who studies violence prevention at UC Davis, told the Los Angeles Times. “Evidence from such studies is not considered to be strong.”

In a commentary published alongside the study in The Lancet, the Harvard School of Public Health's David Hemenway echoed the concern, noting the impressive claim of a 90 percent reduction with just three laws. “That result is too large—if only firearm suicide and firearm homicide could be reduced so easily,” he wrote.

Still, the authors defend their analysis and emphasize that the study highlights the need to focus on gun control measures that definitively work at reducing gun-related deaths. Currently in the US, guns kill about 90 people every day.

"This study is the first big step to figure out which of all the gun laws seem to be effective," Bindu Kalesan, a quantitative social researcher at Boston University and lead author of the study, told CNN.

Overall, the researchers found that nine laws linked to increases in gun deaths, nine associated with decreases, and the remaining seven had inconclusive effects.

According to the study, the nine laws associated with increased gun deaths included:

requirement for the dealer to report records to the state for retention, allowing police inspection of stores, limiting the number of firearms purchased, a 3-day limit for a background-checks extension, background checks or permits during gun shows in states without universal background-check requirement (ie, closure of the gun show loophole), integrated or external or standard locks on firearms, a ban or restrictions placed on assault weapons, law enforcement discretion permitted when issuing concealed-carry permits, and stand-your-ground.

The nine associated with decreased gun deaths were:

state license to sell firearms, keeping and retaining of sales records, at least one store security precaution, firearm identification [either microstamping or ballistic fingerprinting], reporting of lost or stolen firearms, universal background checks for all firearms, safety training or testing requirement to purchase firearms, law enforcement involvement in obtaining of permits, and background checks for the purchase of ammunition.

The Lancet, 2015. DOI: 10.1016/S0140-6736(15)01026-0 (About DOIs).