dgu

Lowell Savage writes: Sorry, Ron. Much as I agree with your position, I have to say that you haven't addressed Tim's issue: why is it that 37% of non-gun defenders were injured before they began self-defensive actions while only 13% of gun defenders were injured before they began self-defense actions? Perhaps an anecdote from a column by Ann Coulter could illuminate a possible explanation. Ann said that she was walking alone over a bridge toward her apartment (or is it a condo? And no I don't remember why she was doing this alone, at that time.) when she saw a man coming toward her from…
In "Point Blank", Kleck analyzed NCVS data and found that while 38% of people who used any means of self-protection against robbers were injured in the encounter, only 17% (the lowest for any means for self-protection) of people who use a gun for self-defence against robbers were injured. Kleck claimed that this showed that guns were the most effective means for avoiding injury. In their critique of "Point Blank" Alba and Messner point out the flaw in Kleck's reasoning -- the evidence from the NCVS is equally well explained if injury makes victims less likely to use guns. Kleck dismisses…
Ray writes: Danny's obvious reading disability has not allowed him to read this when I posted it before. Maybe he can get a friend to read it to him this time: W A Collier writes: Ray, one question for you: If all these other folks including Marvin E. Wolfgang (widely acclaimed as a statistician) found no fault serious enough to invalidate the methodology of Kleck, then how do you account for your posting? Are you a better analyst than Wolfgang and Kleck/Gertz - or are you simply making up a some of this, cutting bits and pieces from their contexts, and then changing contexts (as I have…
W A Collier writes: How the NCVS miscounted DGUs Undersized sample, poor methodology, bias in the questions, unsound methods and procedures in eliminating bias, and unlike Kleck, they started with the conclusion (there are only a small number of gun defenses) as an objective to be proven (not the scientific method) whereas Kleck started with the question (How many DGUs are there) and let the numbers supply the answer, pro or con. You need to inform yourself better about the NCVS. The sample size is about 100 times that of Kleck's survey. The NCVS methodology has been refined over 25 years…
I argued that the estimate of 200,000 DG woundings derived from Kleck's survey (p163 of TG) was inconsistent the estimate of 7700-18,500 DG woundings on page 164 of TG. Kleck accuses me of sloppy reading for not noting that the p 164 estimate is for medically treated wounds only. However, even if we accept Kleck's generous estimate that there are as many untreated gunshot wounds as treated ones (chapter 1 of TG), it is quite clear that if we multiply the page 164 estimate by two to allow for this possibility, that it is still not at all close to the estimate from Kleck's survey. In any case…
Gary Kleck writes: my position that estimates of DGUs with a wounding are unstable is correct. The prevalence of DGUs with a wounding in the Kleck-Gertz (K-G) survey was 0.0011 (1.326% of U.S. adults had a DGU of some kind in the previous year, and 8.3% of DGUs involved a wounding -- see pp. 184-185 of K-G article; 0.083 x 0.01326 = 0.00110058). Assuming simple random sampling, the 95% confidence interval estimate of the national annual prevalence of DGUs with a wounding would be 0.0011 +/- 1.96((.0011 x .9989)/4,977)) = 0.0011 +/- 0.0009, or 0.000179-0.00202. This is not the correct way to…
I used to believe that Kleck's estimate of DGU's was correct, but overwhelming evidence to the contrary has convinced me otherwise. Sam A. Kersh writes: To the best of my knowledge, you have never accepted Kleck's DGU estimates. At least not in the last 5 years that you and I (and Pim) have debated guns, crime and 'Point Blank.' Here's what I wrote about it back in 1991: A most interesting paper! Like any good scientific paper it raises a lot of questions. The estimate of 1M defensive uses arises from about 50 (4% of 1228) yes respondants. Don't you just want to have a follow-up survey…
Dr. Paul H. Blackman writes: Just a very few comments: Folks can report an incident to the police without reporting gun use. I once fetched a gun to encourage some burglars to leave, and reported the burglary but not the gun use, since the gun possession was unlawful. The Kleck estimate is not just inconsistent with police records of gun use against crime, but with police records of crime. There were 300,000 DGUs amongst the robberies known to the police? Are we to suppose that criminals seek out armed victims. Kleck/Gertz have a nice response to the ludicrous Hemenway reliance on…
0. Introduction Volume 87:4 of the Journal of Criminal Law and Criminology contains three articles on the issue of the frequency of defensive gun use. The first presents David Hemenway's critique of Gary Kleck's 2.5 million estimate, the second is Kleck and Gertz's reply and finally Tom Smith of the National Opinion Research Center comments on both papers. I'll try to summarize the arguments and comment where I think they are wrong. 1. Hemenway's critique 1a. False Positives Hemenway's critique has two main arguments. The first is the problem of false positives. Let me define some terms…
John Briggs writes: Also, the Crime Incident Report that follows the Basic Screen Questionnaire seems to elicit details (including defensive responses) regarding only the most recent of multiple similar reported crime incidents. Questions 2 and 3 ask about the when and where of "this/the first incident" and question 4 asks "Altogether, how many times did this type of incident happen during the last 6 months?" Then, item 5a states "The following questions refer only to the most recent incident" and the rest of the questions in the CIR, including those regarding defensive actions, appear to be…
Note that even if you are in love with Kleck's estimate for DGUs, you can't honestly compare it with the NCVS estimate for gun crimes, since it is not possible for both Kleck's estimate for DGUs and the NCVS estimate for gun crimes to be correct. Dr. Paul H. Blackman writes: Why not? NCVS's purpose is to measure crimes, not defensive gun uses. Why can't one think the NCVS does a pretty good job measuring what it's trying to measure, and Kleck-Gertz did a pretty good job measuring what they were trying to measure? Kleck did, of course; Kleck does not seem to have noticed that his "generous…
A large number of criminal shootings are "drive-bys" --- fired from long range and more likely to hit an extremity than a self-defence shooting at close range. These factors suggest that defensive shootings would be more lethal than criminal ones. John Briggs writes: Any data on the proportions of such long range shootings? I confess I have not seen a serious treatment of the topic. News acounts leave one with the impression that such shootings involve whole carloads of machinegun equipped gangbangers. Our streets aren't that wide here in the US. We aren't talking 100 yard firefights.…
John Briggs writes: [Calculation of number of justifiable shootings deleted] This would suggest 15,000 to 20,000 civilian justifiable woundings or 17,500 to 22,500 incidents in which a civilian shot and hit an assailant. Kleck does a similar calculation in "Point Blank" to get an estimate of 10,000 to 20,000. For reasons I allude to below I am inclined to believe that civilian DGUs would be likely to result in a significantly lower killed-to-wounded ratio than would criminal gun use. The 10% to 15% lethality ratio of gunshots may lump together much higher kill-ratio criminal shootings…
John Briggs writes: [Calculation of number of justifiable shootings deleted] This would suggest 15,000 to 20,000 civilian justifiable woundings or 17,500 to 22,500 incidents in which a civilian shot and hit an assailant. Kleck does a similar calculation in "Point Blank" to get an estimate of 10,000 to 20,000. (This represents an awfully high figure if there are only 80,000 civilian DGUs as the NCVS reports--of course, the NCVS could be low.) As you have noted, if we know A, the fraction of DGUs where the defender shot at the criminal, and B, the fraction of DGUs where one or more of the…
SFBearCop wrote: I can think of a number of reasons, none of them noble, why someone would fabricate a DGU, starting with giving the pollster what they thought was wanted. People do it all the time, so a friend in the public-opinion-counting game told me thirty or more years ago. John Briggs writes: This would account for some false positives in the DGU surveys. It would also be present, presumably, in NCVS responses. The question is why are the response rates so different? The DGU question appears quite early in Kleck`s survey. It's not hard for a person to guess that it is the important…
Peter Boucher writes: Just in case anyone's interested. Copied from Kleck/Gertz, here are the polls from table 1 (minus those with no estimate of annual DGUs): Survey, Where, What year, What kinds of guns, # DGUs Field, California, 1976, just handguns, 3.1M Bordua, Illinois, 1977, all guns, 1.4M DMIa, U.S., 1978, all guns, 2.1M DMIb, U.S., 1978, all guns, 1.1M Hart, U.S., 1981, just handguns, 1.8M Ohio, Ohio, 1982, just handguns, 0.8M Mauser, U.S., 1990, all guns, 1.5M Gallup, U.S., 1991, all guns, 0.8M Gallup, U.S., 1993, all guns, 1.6M L.A.Times, U.S., 1994, all guns, 3.6M Tarrance, U.S.,…
"Eugene Volokh" writes: but I was wondering what you thought about the NCVS point I raised again a few days ago. To my knowledge, waiting for respondents to volunteer information is generally considered rather bad survey practice; and we saw that with the rape statistics shifting to a direct question changed the total by about a factor of 2.5 or 3, if I recall correctly. I have even been told -- entirely outside the defensive gun use context -- that the trick is cuing as often as possible: Asking the question directly, several times, in subtly different ways, to trigger people's memories…
Dr. Paul H. Blackman writes: I was curious about the suggestion that hardly anyone could possibly still believe the Kleck data now that NSPOF had become the 15th or 16th such survey in the same general category. Then you seem to have misunderstood. Kleck's estimate (not his data - I have no problem with his data, just his interpretation of it) is not credible because it fails every single cross check of its validity. It is inconsistent with: CDC counts of homicides UCR counts of homicides Kleck's own, earlier, estimate of defensive woundings Kleck's own, earlier, estimates of defensive…
Peter Boucher writes: Tim wrote that he, at first, agreed with the Kleck DGU estimates, but has since been convinced by the evidence that they were wrong. Tim, I've known you (well, sort of) for over 5 years, and I've never seen you post anything that indicated that you agreed with Kleck's DGU estimates. Did you change your mind more than five years ago? What was the evidence that forced you to change it? I first encountered one of Kleck's estimates in his paper published in "Social Problems". This was in 1989, soon after I first started posting to talk.politics.guns. In this paper he…
"Eugene Volokh" writes: I should say that I agree with some of your criticisms of the Kleck & Gertz results, and of the 1.5 million count arrived at by the NSPOF study; In case anyone remains who finds the Kleck estimate credible, let me make a couple more observations: On page 170 Kleck "generously" estimates that there are about 550,000 gun crimes each year. According to his survey, in about 18% of his 2.5M DGUs, the offender was armed with a gun. That's about 450,000 gun crimes. Apparently we are supposed to believe that in 90% of gun crimes the victim gets to use a gun for…