Friday, April 27, 2018

CDC Failed to Report Strong Evidence of Defensive Gun Uses

Dr. Gary Kleck

Gary Kleck, the award winning criminologist who documented significant levels of defensive gun use (DGU) in American society, has uncovered research done by the CDC that strongly corroborates his findings.  Kleck  and Gertz's seminal study was done in 1993, presented in 1994, and published in 1995.

The CDC research was done in 1996, 1997, and 1998, but was never publicized.

The BRFSS surveys are high-quality telephone surveys of enormous probability sample of U.S. adults, asking about a wide range of health-related topics. Those that addressed DGUasked more people about this topic than any other surveys conducted before or since. For example, the 1996 survey asked the DGU question of 5,484 people. The next-largest number questioned about DGU was 4,977 by Kleck and Gertz (1995), and sample sizes were much smaller in all the rest of surveys on the topic (Kleck 2001). 

The wording of the DGU question in the BRFSS surveys was also excellent, addressing many problems with the wording of the DGU questions used in other surveys. The exact wording was:

“During the last 12 months, have you confronted another person with a firearm, even if you did not fire it, to protect yourself, your property, or someone else?”
Respondents had previously been instructed not to report firearm uses associated with an occupation that “requires and authorizes you to use a firearm.” Thus, the question excluded uses by police and others with firearm-related jobs. Further, the question appropriately excluded uses against animals (“...another person...”), asked about a specific, recent recall period (“during the last 12 months”), covered uses by any type of firearm (not just handguns), covered uses regardless of where they occurred (not just uses in the home), and explicitly told respondents that they should report uses even if they did not fire a gun. In sum, the surveys used an excellent, carefully worded DGU question, in contrast to the wordings used in so many other surveys (Kleck 2001).     
The CDC did not directly mention the results of the 1996, 1997, and 1998 research in the paper done on gun control that was overseen by the CDC in 2013. That paper had been asked for President Obama.  Defensive gun use research was considered. From the 2013 CDC paper
Defensive Use of Guns

Defensive use of guns by crime victims is a common occurrence, although the exact number remains disputed (Cook and Ludwig, 1996; Kleck, 2001a). Almost all national survey estimates indicate that defensive gun uses by victims are at least as common as offensive uses by criminals, with estimates of annual uses ranging from about 500,000 to more than 3 million (Kleck, 2001a), in the context of about 300,000 violent crimes involving firearms in 2008 (BJS, 2010). On the other hand, some scholars point to a radically lower estimate of only 108,000 annual defensive uses based on the National Crime Victimization Survey (Cook et al., 1997). The variation in these numbers remains a controversy in the field. The estimate of 3 million defensive uses per year is based on an extrapolation from a small number of responses taken from more than 19 national surveys. The former estimate of 108,000 is difficult to interpret because respondents were not asked specifically about defensive gun use.
The paragraph above does not rule out the surveys done by the CDC. It says that "more than 19 national surveys" not "19 national surveys".  Were the authors aware of the CDC surveys done in 1996, 1997, and 1998, that essentially confirmed the estimates made by Kleck and Gertz in the 1995 paper?

The  timing and size of the surveys done by the CDC is fascinating. They were done immediately after Kleck and Gertz published their paper. There were three of them. The one in 1996 was the largest ever done.  5,884 people were asked the DGU question. The total number of people asked in the three surveys done by the CDC was 12,870. All were asked the same question. It is as if a single very large survey was done, over three years. Kleck and Gertz' survey asked their DGU questions of 4,977 people.

Kleck goes into considerable detail about how his survey, done in 1993 (published in 1995) differs from the CDC survey. For example, in the CDC survey, only those people who admitted to having a gun in the home were asked the DGU question.

When Kleck applies the corrections to adjust for the differences in the surveys, the results are spectacularly close. Kleck and Gertz survey arrived at a number of 1.326% in 1995. The average in the three CDC surveys is 1.24%.  The first, and largest survey (closest in time to the Kleck and Gertz survey) had a  slightly larger number, and the two later surveys had a little smaller number.

Those numbers indicate about 2.5 million defensive gun uses a year in the United States, at a minimum. The numbers do not consider defenses against animals. There may be more defenses against animals than against people. I disagree with Kleck about excluding defenses against animals. Defending against an animal is just as real as defending against a person. Kleck mentions the strong possibility of false negatives, because nearly as many people answered "do not know" and "refused to respond" as answered affirmatively to the DGU question.

Having read the Kleck and Gertz paper, I often wished that someone would do another survey, to broaden the sample, to provide more data.

Now we find the CDC did three such surveys. All of them validated the Kleck and Gertz survey. One large survey, such as the one by Kleck and Gertz, is indicative. Four of them show scientific replication and add to certainty. We were never told of the results of the confirming surveys done by the CDC.

Gary Kleck, as a scientist, a Democrat, and a proponent of a number of gun control measures, is careful not to cast aspersions on the CDC. He does not accuse anyone of malfeasance. He notes the surveys were done during the Clinton administration, and these findings would have worked against the gun control agenda of the administration. Someone at the CDC made the decision not to publish these results.

Kleck, while doing research, happened to come across the DGU question in a historical CDC survey, online, 21 years after the CDC surveys had been completed.

He was intrigued, and was able to find the original surveys done in 1996, 1997, 1998, and all the results.

It has to be gratifying to Dr. Kleck, to see his results validated after more than two decades. It may be infuriating to know these results were available from 1997 to 1999, and were never made public.

©2018 by Dean Weingarten: Permission to share is granted when this notice and link are included.

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1 comment:

Anonymous said...

Now why might the CDC have possibly made such an oversight?