Sen. Chris Murphy, D-Conn., one of Congress’ leading advocates of stricter gun laws, recently tweeted a statistic that he said shows that more restrictive gun laws can save lives.

“The 5 states with the highest gun homicide rates in the nation all have loose gun laws” while “the 5 states with the lowest rates have some of the toughest laws,” Murphy tweeted April 3.

Murphy listed what he said were the top five states for gun homicide rates: Alaska, Alabama, Montana, Louisiana and Mississippi (though he incorrectly used the postal abbreviation for Michigan). These states each have a failing grade on gun laws from the Giffords Law Center, which supports laws to prevent gun violence.

The states he said had the lowest gun homicide rates were Hawaii, New York, Massachusetts, Rhode Island and Connecticut. Those states have high marks from Giffords for gun laws, because they have policies such as universal background checks, assault weapon restrictions, a large capacity magazine ban and strong concealed carry laws.

Shortly after Murphy tweeted, a reader sent PolitiFact the link and asked whether Murphy’s claim is correct.

When we examined the claim further, we found issues with Murphy’s framing of the data and his oversimplified conclusion.

Twitter attached a note to Murphy’s tweet based on crowdsourced feedback. It said that the numbers in his cited source, a webpage at the World Population Review website, represent gun deaths per capita, which include suicides, not just homicides.

Noticed that the data I cited was not “homicides”. It’s actually total “gun deaths”, which includes suicides.

This just strengthens the argument that gun laws make a difference.

— Chris Murphy (@ChrisMurphyCT) April 6, 2023

Responding to PolitiFact’s inquiry, Murphy’s press office acknowledged the mistake, and his Twitter account appended a reply noting the discrepancy.

Regardless of how suicides shift the data, the connection between gun laws and death rates is still not as direct as Murphy presented.

Some states with less restrictive gun laws — such as Nebraska, North Dakota, Idaho, Maine, New Hampshire and Vermont — have low rates of gun homicides.

And some states with restrictive gun laws, including Illinois and Maryland, have high rates of gun homicide.

Experts say that factors beyond gun laws can influence a state’s gun homicide rate.

“There is no simple correlation of gun control severity and violence rates,” said Gary Kleck, a Florida State University emeritus professor of criminology.

How the states rank

The most readily available data, from websites like Giffords’ and World Population Review, tends to use overall gun deaths, not just gun homicides. So, there can be confusion when people, including Murphy, try to cite data on homicides and offer instead overall data for homicides and suicides.

This is not a trivial difference. According to the Centers for Disease Control and Prevention, the U.S. in 2020 had 19,384 gun homicides but a significantly larger number of suicides: 24,292. An additional 535 gun deaths were ruled accidental, 611 were due to law enforcement intervention, and 400 were undetermined. So homicides in 2020 accounted for about 43% of all gun deaths.

Suicides are an important issue within the category of gun violence. However, because Murphy’s tweet specifically cited the link between gun homicide and gun laws, we wanted to test his original proposition. We collected state-by-state gun homicide data using an online tool run by the CDC. Using data filters, we looked at states’ rate of gun homicides and fatal law enforcement shootings per 100,000 residents in 2020.

We layered the state homicide data with an assessment of gun laws by Guns & Ammo magazine, which is geared toward gun owners. The magazine uses a 50-point scale to rate each state on the strictness of its gun laws, with 50 being the least restrictive.

Using the homicide data alone, without including suicides, changes the roster of highest- and lowest-ranking states for homicides from what Murphy said in his tweet.

CDC data shows the five states with the highest gun homicide rates were Mississippi, Louisiana, Alabama, Missouri and South Carolina. These states have some of the nation’s most permissive laws on guns, such as allowing guns to be carried without a permit and having barriers to enforce federal gun laws.

Using the CDC data, the five states in 2020 with the lowest gun homicide rates were Vermont, New Hampshire, Maine, Idaho and Hawaii. Notably, most of those states were not included in Murphy’s initial tweet, and all except Hawaii have relatively permissive gun laws.

Other states within the list of bottom 10 gun homicide rates, notably Nebraska and North Dakota, also have relatively permissive laws, according to the Guns & Ammo ranking. States with tighter gun laws, including Massachusetts, Rhode Island and Minnesota, are also in the bottom 10.

Other factors beyond gun laws

A key complicating factor that Murphy ignores is region.

The list of 10 states with the highest gun homicide rates, according to the CDC, includes seven in the South: Mississippi, Louisiana, Alabama, South Carolina, Tennessee, Arkansas and Georgia.

By contrast, the bottom 10 mostly includes states that are northeastern (Vermont, New Hampshire, Maine, Massachusetts and Rhode Island) or are in the Great Plains or Rocky Mountain regions (Idaho, North Dakota, Minnesota and Nebraska).

Beyond historical-cultural factors, many of the states with high gun homicide rates have higher poverty rates and less developed trauma care resources, both of which can affect death rates from gun violence, said Jay Corzine, a University of Central Florida emeritus professor of sociology and a homicide and gun policy expert.

Meanwhile, some states that have tight gun laws and large cities with poverty and gang activity rank relatively high, such as Illinois and Maryland.

“There is certainly a correlation between gun laws and gun violence rates, but determining causation is virtually impossible,” said Jaclyn Schildkraut, executive director for the Rockefeller Institute of Government’s Regional Gun Violence Research Consortium in Albany, New York. “There are too many variables at play, some of which cannot be controlled for.”

Our ruling

Murphy tweeted, “The 5 states with the highest gun homicide rates in the nation all have loose gun laws” while “the 5 states with the lowest rates have some of the toughest laws.”

Murphy is partially accurate when he said the top five states for gun homicide death rates include only states with looser gun laws. However, his framing ignores that several states with relatively loose gun laws have low gun homicide rates, and some states with tighter laws have relatively high gun homicide rates.

Experts say other variables, including region, poverty and medical infrastructure,  also shape the gun homicide rate.

The statement is partially accurate but leaves out important information. So, we rate the statement Half True.

This fact check was originally published by PolitiFact, which is part of the Poynter Institute. See the sources for this fact check here.