Brain357
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- Mar 30, 2013
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And some more on hemenway...
If Hemenway really did believe that the NCVS estimates are approximately accurate, he may well be the last scholar in this field to cling to this belief. After touting the NCVS estimates of DGU for years, even authors as strongly wedded to the rare-DGU position as Philip Cook (Cook 1991; Cook and Moore 1994) and David McDowall (McDowall and Weirsema 1994) have ceased portraying the NCVS estimates as valid. Instead, they have shifted to the agnostic views that (1) no survey, including the NCVS, can yield meaningful estimates (Cook and Ludwig 1996; 1997) or that (2) “the frequency of firearm self-defense is an issue that is far from settled” (McDowall 1995), views incompatible with the position that the NCVS estimates are at least approximately valid and therefore have settled the matter. By December of 1994, Cook had taken a position directly contradicting Hemenway’s seeming acceptance of the NCVS estimates, stating that there are “persuasive reasons for believing that the [NCVS] yields total incident figures that are much too low” (Kates et al. 1995, p. 537, quoting a December 20, 1994 letter from Cook). Echoing these views, another strongly pro-control scholar, Tom Smith, has written that “it appears that the [DGU] estimates of the NCVSs are too low” (1997, p. 1462).
Kleck and Gertz provided a detailed explanation of why the NCVS grossly underestimates DGU frequency, and noted that its DGU estimates had been repeatedly disconfirmed by other surveys (1995, pp. 153-157). Still, Hemenway gave the impression that he was using the NCVS estimates as a standard against which he judged the DGU estimates of other surveys (Hemenway 1997b, pp. 1431-1432). In this connection, he falsely claimed that the NCVS asks “about self-defense gun use” (p. 1432) when in fact, as Kleck and Gertz pointed out, one of the many problems with the NCVS as a vehicle for estimating DGU frequency is that it never directly asks respondents about DGU (1995, p. 155). Instead it merely provides respondents with an opportunity to volunteer information about a DGU in response to a general question about self-protection actions.
As Tom Smith, Director of the National Opinion Research Center, has noted, specifically in connection with the NCVS: “Indirect questions that rely on a respondent volunteering a specific element as part of a broad and unfocussed inquiry uniformly lead to undercounts of the particular of interest” (Smith 1997, pp. 1462-1463).
Nor did Hemenway acknowledge that the NCVS is the only survey that has ever yielded annual DGU estimates under 700,000, and that its estimates, centering around 80,000, are far below those generated by at least fifteen other surveys (Kleck and Gertz 1995, pp. 153-159). Instead, he inverted reality by falsely hinting that it was the NSDS estimate that was the deviant result.
It is tempting to think that the NCVS estimates should be given greater credibility than any one survey because the NCVS has been continuously fielded since 1973, and thus could be regarded as, in some sense, a series of surveys rather than just one survey, which have provided independent confirmation of low DGU estimates. Hemenway himself, however, noted that “consistency of findings is irrelevant when the methodology among...the surveys is similar.” He made this point with respect to the DGU surveys, but it is far more applicable to the NCVS, since great care has been taken to keep the NCVS, despite periodic revisions, consistent over time. In contrast, there was, contrary to Hemenway’s claims, great diversity in methodology among the DGU surveys (Kleck and Gertz 1995, pp. 157-160).
The NCVS is more accurately viewed as a single ongoing survey, with interviews conducted monthly since 1973 by the same government agency, using methods intentionally kept extremely consistent from 1973 right up to a redesign in 1992. Thus, the flaws that afflicted the NCVS for measuring DGUs in 1973 were, for the most part, still with it in 1992 when the McDowall and Wiersema (1994) and Cook (1991) estimates that Hemenway favorably cited (1997b, p. 1432) were generated. We can only heartily agree with Hemenway that reproducing the same result over and over with the same flawed measurement tool does not provide much evidence about anything. Hemenway just got it wrong as to which surveys this observation is best applied to.
Again, where does he defend this:
Hemenway put together facts from the well-regarded NCVS—that someone was known to be home in just 22 percent of burglaries (1.3 million), and that fewer than half of U.S. households have firearms—and pointed out that Kleck “asks us to believe that burglary victims in gun-owning households use their guns in self-defense more than 100 percent of the time.”
You can't do something over 100 percent of the time...
This might help.....
Although we systematically rebut each of Hemenwayls H claims we
10. Fallacious Reasoning––Hemenway’s “Checks on External Validity”
In their original article, Kleck and Gertz cautioned against two kinds of fallacious reasoning. Instead of taking the warnings seriously, Hemenway seems to have treated them as signposts to deceptive arguments that might prove useful for propagandistic purposes. Both fallacious arguments involve a misapplication of reductio ad absurdum argumentation, based on the misperception that estimates from the NSDS were inconsistent with known crime counts and the erroneous assumption that the NCVS provides correct estimates of the absolute frequency of crime.
Hemenway argued that the NSDS estimates are implausible because this survey implied a number of DGUs occurring in connection with burglaries that exceeded the total number of burglaries of occupied residences estimated by the NCVS, and thus the DGU estimate was impossible, or at least implausibly high (p. 1441). This argument rested on an unstated assumption that the universe of DGU events sampled by the NSDS is a subset of the universe of crime events covered by the NCVS. However, Kleck and Gertz had explicitly warned in their paper that “a large share of the incidents covered by our survey are probably outside the scope of incidents that realistically are likely to be reported to the NCVS or police” (1995, p. 167). This is true because DGUs typically involve criminal behavior, such as unlawful gun possession, by the gun-using victim, who therefore is often unwilling to report the incident. Once it is recognized that many DGU events are outside the realm of crime incidents effectively covered by the NCVS, it is logically impossible to treat any NCVS estimates as imposing an upper limit on how many DGUs there plausibly could be.
Hemenway’s logic was also fallacious in assuming that one can cast doubt on conclusions based on a large body of data by deriving implausible implications from smaller subsets of the data. The NSDS estimates of total DGUs are likely to be fairly reliable partly because they are based on a very large (n=4,977) sample, while any estimates one might derive pertaining to one specific crime type are necessarily less reliable because they rely partly on a far smaller subsample, i.e. the c. 194 sample DGU cases, of which 40 were linked to burglaries.
Hemenway’s reductio ad absurdum logic is equivalent to arguing that Gallup presidential election polls cannot accurately estimate the share of the entire electorate voting for the Democratic candidate (something we know they can do, usually to within two percentage points––Gallup 1992) because they commonly yield implausible estimates for small subsets of the electorate, such as rural Hispanic Jews. One undoubtedly could obtain implausible estimates of voter preference for the Democratic candidate, such as 0% or 100%, based on a very small number of sample cases, for many subsets of the population. This would imply nothing, however, about the ability of the survey to estimate voter preferences in the entire population. Thus, even if estimates of DGUs linked to a given specific crime type were implausible, which they are not, this would imply nothing about whether estimates of the total number of DGUs, based on the full sample, are accurate.
Finally, even if one ignored these logical fallacies, Hemenway’s argument still would fail, because it depends on an indisputably erroneous assumption. Hemenway stated that “from the NCVS, we know that there were fewer than 6 million burglaries in 1992” (1997b, p. 1441), and made similar statements about rapes (p. 1442). In fact, we do not “know” any such thing. No competent criminologist believes that the NCVS provides complete coverage of all burglaries, or any other crimes, occurring in the U.S. And once one concedes that there may be far more crimes than the NCVS estimates, Hemenway’s argument collapses,
since it becomes impossible to argue that estimates of the number of DGUs linked to a given type of crime are implausibly high relative to the total number of crimes of that type––we simply do not know the latter number.
In a second variety of this fallacious line of reasoning, Hemenway cited estimates of the number of gunshot wound (GSW) victims treated in emergency rooms and falsely claimed that “K-G report that 207,000 times per year the gun defender thought he wounded or killed the offender” (1997b, p. 1442). In fact, Kleck and Gertz did not compute or report this 207,000 estimate. Quite the contrary––they specifically cautioned against using NSDS data to generate such an estimate because an estimate of defensive woundings would be based (unlike the estimates of DGU frequency in general) on a small sample (the approximately 200 respondents who reported a DGU) and because NSDS interviewers had done no detailed questioning of respondents regarding why they thought that they had wounded their adversaries.
In any case, there is nothing even mildly inconsistent about this GSW estimate and emergency room data on persons treated for GSWs. Hemenway necessarily made the implicit assumption that DGU-linked woundings are entirely a subset of woundings treated in medical facilities. If one more plausibly assumes that most less serious DGU-linked woundings are not medically treated, the number of medically treated GSWs cannot be used as an upper limit on the number of DGUs that result in a wounding, since DGU-linked woundings would exist largely outside the set of medically treated GSWs. If, for example, the total annual number of GSWs, treated or untreated, was 400,000, there would be nothing implausible about 200,000 of them being DGU-linked, especially in light of the fact that the vast majority of victims of medically treated GSWs linked to alleged “assaults” are known criminals (Kleck 1997, Chapter 1).
It is unlikely that a criminal wounded by a victim during the commission of a crime would seek medical attention for any but the most life-threatening GSWs, since medical personnel are required by law to report treatment of GSWs to the police. Less than a tenth of assault GSWs are life-threatening (Kleck 1997, Chapter 1). Thus, almost all of the DGU-linked woundings of criminals probably lie outside the universe of GSWs treated in emergency rooms and other medical facilities. The number of medically treated GSWs therefore cannot serve as an upper limit on either the total number of GSWs or on the number that occur in connection with a crime victim’s DGU. In sum, since we do not know the total number of crime victimizations such as rapes or burglaries, or the total number of GSWs, we cannot possibly know if any given DGU estimate is implausibly large relative to these unknown (and possibly unknowable) quantities.
It is worth stressing that crucial logical fallacies in Hemenway’s reductio ad absurdum arguments were explicitly noted in the original 1995 article by Kleck and Gertz (pp. 167-168, 172-174), before Hemenway presented them. Thus, because Kleck and Gertz had explicitly warned against making the very arguments that Hemenway would later make, Hemenway was clearly aware of the fatal flaws in his arguments. Since he did not rebut any of the arguments that Kleck and Gertz used to conclude that this line of reasoning was fallacious, it is reasonable to conclude that when Hemenway made his reductio ad absurdum arguments, he knew they were fallacious. Thus, his use of these arguments can be reasonably viewed as part of an intentional effort by Hemenway to deceive his readers, and not merely the product of sloppy thinking.
From above:
This is true because DGUs typically involve criminal behavior, such as unlawful gun possession, by the gun-using victim, who therefore is often unwilling to report the incident.
So again, criminals defending criminals. That is not a defense, it is a crime.
