However, there are problems with the study. Big problems.
U.S. gun laws vary considerably by state. Some, like Kansas, allow citizens to carry firearms in public and make it legal for gun owners to shoot an assailant in self-defense in some situations (known as the stand your ground doctrine). Others, like California, are more restrictive, limiting not only who is allowed to carry guns in public, but also access to firearms in the home by requiring safety devices such as trigger locks or gun safes.