NIJ Study: Defensive Gun Uses

A while back, I mentioned that I would be spending a little more time with the much debated National Institute of Justice study from 1994 as I felt there are some interesting data points in the research that have been ignored by many. One section of the study that I felt could use some discussion is the section covering yearly defensive gun uses (DGUs).

As part of the NIJ’s phone survey, respondents were asked not only about firearm acquisition methods, but also about uses of firearms to prevent or defend against crimes. The opening question asked by the NIJ in this part of the study was, “[w]ithin the past 12 months, have you yourself used a gun, even if it was not fired, to protect yourself or someone else, or for the protection of property at home, work, or elsewhere?”. Those who answered with a “yes” were then asked a series of questions relating to their defensive usage scenarios. Based on the polling, the following statistics were revealed:


As we can see from the data, 45 individuals, or approximately 1.6 percent of the total study sample responded that they had used a firearm defensively in the 12 months preceding the study. Based on the makeup of the study, this number translates to 3.1 million defenders each year. Because later questions asked whether individuals had used firearms in defensive scenarios multiple times during the year, an estimate of 23 million DGUs was generated. The estimate of 3.1 million defenders per year is very much in line with the 1995 study performed by Gary Kleck at Florida State. Using Kleck’s stricter definition of a DGU (respondent must see the perpetrator, respondent must state a specific crime that was being committed, respondent must have mentioned or presented the firearm), the NIJ study still found that approximately 1.5 million people use firearms to defend themselves each year. It should be noted that this is still reasonably close to the 2.5 million figure generated by the Kleck study.

With the above in mind, the NIJ study offers some explanation for why the 23 million yearly DGUs might be an exaggeration. One study used to critique the 23 million figure is the National Crime Victimization Survey (NCVS). According to NCVS data, firearms are used defensively around 108,000 times per year, which is still quite substantial. In discussing the NCVS study, the NIJ asserts that the NCVS manages to prevent false-positives (respondents claiming DGUs falsely) by requiring respondents to have first acknowledged being crime victims. Additionally, the NIJ reports that a few respondents reported having used firearms defensively an inordinate number of times during the previous year (one as may as 50 times).

Although the NIJ does seem to identify partly why their numbers run higher than expected, the assumption that the NCVS survey was somehow more valid than the NIJ or Kleck methodology is questionable. For one, it is highly likely that a significant number of defenders would not claim to have been victims of any crime. Certainly, they could easily argue that the presence of their firearm prevented the commission of any crime. For the NCVS to require respondents to claim victim status prior to asking about DGUs is not a sufficiently sound way to discredit false-positive cases and it is likely that some true-positives were eliminated based on respondents’ unwillingness to claim victim status.

In conclusion, if the methodology and findings of other portions of the NIJ study are going to be touted as valid as we have seen with the study’s analysis of firearm acquisitions, we must be willing to apply the same standards to the rest of the study. Though the study’s finding that firearms are used 23 million times each year to prevent crime is quite likely an exaggeration, based on the questions asked a figure of 1.5 million defenders each year, or 1 in every 100 adults, is not completely unreasonable and is in line with previous studies, such as that carried out by Florida State’s Gary Kleck. Furthermore, as has been mentioned several times before, the NIJ data is relatively old at this point. At the time of the study, 12 states prohibited concealed or open carry of a handgun. In comparison, today only one state, Illinois, maintains such restrictions and will be soon moving to create a licensing system for carrying. In the time since the 1994 survey, there has been an increase in the number of people carrying firearms legally for personal protection. With this in mind, it is entirely possible that the numbers today may be even more favorable than at the time of the NIJ or Kleck studies.

Original Study:


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