We use epidemiological theory to explain why the "false positive" problem for rare events can lead to large overestimates of the incidence of rare diseases or rare phenomena such as self-defense gun use. We then try to validate the claims of many millions of annual self-defense uses against available evidence. We find that the claim of many millions of annual self-defense gun uses by American citizens is invalid.

Hemenway, David. Survey research and self-defense gun use: An explanation of extreme overestimates. Journal of Criminal Law and Criminology. 1997; 87:1430-1445.

Hemenway, David. The myth of millions of annual self-defense gun uses: A case study of survey overestimates of rare events. Chance (American Statistical Association). 1997; 10:6-10.

Cook, Philip J; Ludwig, Jens; Hemenway, David. The gun debate's new mythical number: How many defensive uses per year? Journal of Policy Analysis and Management. 1997; 16:463-469.

4. Most purported self-defense gun uses are gun uses in escalating arguments and are both socially undesirable and illegal 

We analyzed data from two national random-digit-dial surveys conducted under the auspices of the Harvard Injury Control Research Center.  Criminal court judges who read the self-reported accounts of the purported self-defense gun use rated a majority as being illegal, even assuming that the respondent had a permit to own and to carry a gun, and that the respondent had described the event honestly from his own perspective.

Hemenway, David; Miller, Matthew; Azrael, Deborah. Gun use in the United States: Results from two national surveys. Injury Prevention. 2000; 6:263-267.

5. Firearms are used far more often to intimidate than in self-defense. 

Using data from a national random-digit-dial telephone survey conducted under the direction of the Harvard Injury Control Center, we examined the extent and nature of offensive gun use.  We found that firearms are used far more often to frighten and intimidate than they are used in self-defense. All reported cases of criminal gun use, as well as many of the so-called self-defense gun uses, appear to be socially undesirable.

Hemenway, David; Azrael, Deborah. The relative frequency of offensive and defensive gun use: Results of a national survey. Violence and Victims. 2000; 15:257-272.

6. Guns in the home are used more often to intimidate intimates than to thwart crime.Using data from a national random-digit-dial telephone survey conducted under the direction of the Harvard Injury Control Research Center, we investigated how and when guns are used in the home. We found that guns in the home are used more often to frighten intimates than to thwart crime; other weapons are far more commonly used against intruders than are guns.

Publication: Azrael, Deborah R; Hemenway, David. In the safety of your own home: Results from a national survey of gun use at home. Social Science and Medicine. 2000; 50:285-91.

We analyzed data from a telephone survey of 5,800 California adolescents aged 12-17, which asked questions about gun threats against, and self-defense gun use by these young people.  We found that these young people were far more likely to be threatened with a gun than to use a gun in self-defense, and most of the reported self-defense gun uses were hostile interactions between armed adolescents.  Males, smokers, binge drinkers, those who threatened others and whose parents were less likely to know their whereabouts were more likely both to be threatened with a gun and to use a gun in self-defense.

Hemenway, David; Miller, Matthew.  Gun threats against and self-defense gun use by California adolescents. Archives of Pediatrics and Adolescent Medicine. 2004; 158:395-400.

8. Criminals who are shot are typically the victims of crime

Using data from a survey of detainees in a Washington D.C. jail, we worked with a prison physician to investigate the circumstances of gunshot wounds to these criminals.
We found that one in four of these detainees had been wounded, in events that appear unrelated to their incarceration. Most were shot when they were victims of robberies, assaults and crossfires. Virtually none report being wounded by a "law-abiding citizen."

May, John P; Hemenway, David. Oen, Roger; Pitts, Khalid R. When criminals are shot: A survey of Washington DC jail detainees. Medscape General Medicine. 2000; June 28. www.medscape.com


9-10. Few criminals are shot by decent law abiding citizens

Using data from surveys of detainees in six jails from around the nation, we worked with a prison physician to determine whether criminals seek hospital medical care when they are shot. Criminals almost always go to the hospital when they are shot. To believe fully the claims of millions of self-defense gun uses each year would mean believing that decent law-abiding citizens shot hundreds of thousands of criminals.  But the data from emergency departments belie this claim, unless hundreds of thousands of wounded criminals are afraid to seek medical care. But virtually all criminals who have been shot went to the hospital, and can describe in detail what happened there. 

May, John P; Hemenway, David. Oen, Roger; Pitts, Khalid R. Medical Care Solicitation by Criminals with Gunshot Wound Injuries: A Survey of Washington DC Jail Detainees. Journal of Trauma. 2000; 48:130-132.

May, John P; Hemenway, David. Do Criminals Go to the Hospital When They are Shot? Injury Prevention 2002: 8:236-238.