Deltoid

"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 defence. This could perhaps help explain the 0.5M DGUs by people from non-gun-owning households -- they merely take the criminal's gun away and use that ;-)

Kleck has no trouble believing that defensive gun use is much more common than criminal gun use because "there are far more gun-owning crime victims than there are gun-owning criminals". Presumably he would have no trouble believing that there were more many criminal victimizations than crimes committed because there are more crime victims than criminals. Of course, what determines the relatively frequency of criminal and defensive gun use is the fraction of criminals that use guns, versus the fraction of victims that use guns. Common sense suggests that since criminals are more likely to be involved in a violent crime than victims, they have a greater incentive to go armed. They can also choose to only commit crimes when armed. Consequently it is reasonable to expect that criminal gun use will be more frequent than defensive gun use.

46% of Kleck's DGUs were by women. As Kleck admits (p178) because men are much more likely to own guns and much more likely to be crime victims, the true percentage should be much less. True to form, Kleck explains this anomaly by supposing that there are millions more DGUs by men that his survey did not pick up. An alternative explanation is that DGUs that are made up do not have to follow actual gun ownership or crime patterns.

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 (and perhaps willingness to respond).

This was considered in the NCVS redesign -- it asks the screening questions in several different ways. This would seem to be better than just having one screening question, as Kleck's survey does.

Am I mistaken about this understanding of general survey practice? If I am correct, doesn't it quite severely undercut the 80,000 estimate (while of course not proving the 2.5 million estimate)?

There are three ways it could be a problem.

Firstly, respondents may forget to mention a burglary when asked directly about it, but they might recall using a gun to defend against a burglar when asked about using a gun for defence.

However, the survey already asks about such crimes in several different ways, so the difference made by asking yet another cueing question would be small.

Secondly, respondents may remember about the crime but forget they used a gun to defend, but be reminded by a question that specifically asked about guns.

I don't see this as particularly likely. Once you are recalling one detail of an incident, other details come to mind.

Thirdly, respondents may be a little reluctant to mention the gun use but a direct question may overcome this reluctance.

This seems possible. I can't guess at how much of a differnece it would make. It would be interesting to do a survey that followed NCVS methodology except for asking a specific question about gun use as well as a general question about defensive actions.

In any case, I believe that a bigger problem is that there are probably quite a few DGUs by criminals who are not going to participate in victimization surveys, and by people who just do not which to recount their DGUs to strangers. So, while the NCVS provides the best available estimate, it probably undercounts, perhaps by as much as a factor of two.

Eugene Volokh:

As pointed out by Tim only a few have addressed gun use in self defense against a crime. The NCS, the Police Foundation and Kleck.

Dr. Paul H. Blackman writes:

No, several have, but not the NCVS, which measures victimization.

It does indeed measure victimization. But this does not prevent it from measuring gun use in self defence against a crime. Are you attempting to deny the very existence of the NCVS estimate of 80,000 DGUs?

Eugene Volokh:

In sample size for instance and response rate the NCS outperforms these surveys significantly.

Dr. Paul H. Blackman writes:

The sample size is lovely; it's kind of a shame it wasn't a survey to measure the protective use of guns.

That's not its sole purpose, but it is one of the things that it was designed to measure. You only have to look at the questions and the categorization of the responses to see that.

Eugene Volokh:

Tim has shown several examples of 'problems' with Suter, not in the least with Suter's selective use of data to 'prove a point'.

Dr. Paul H. Blackman writes:

Gee, and I thought Suter's selective use of data to prove a point -- specifically, citing a few high-crime/low-gun and a few low-crime/high-gun jurisdictions

You forgot to mention that he claimed they were representative.

-- was just a cutesy imitation of what Zimring and the "gun control" movement have been doing without criticism for three decades or more, designed to show what would happen if pro-gunners attempted the "science" of anti-gunners.

I have provided a specific example of Suter's deliberately deceptive practices. Practices which you apparently condone. If you want to claim that Zimring has done something similar, you need to provide some evidence.

Incidentally, I understand that Killias and Kleck each submitted affidavits in Canada regarding the court challenge to their new law. But, under the Canadian system, for the affidavit to count, the expert has to defend his statements from examination/cross-examination -- presumably with the lawyers questioning being assisted by some other expert (Killias to help the lawyers questioning Kleck and Kleck helping the lawyers questioning Killias). Under the circumstances, Killias dropped out rather than defend his affidavit from a lawyer assisted by Kleck. It's probably just modesty, a professorial fear of performing in public.

More likely the trip across the Atlantic made it a bit inconvenient. You seem to be insinuating that he was afraid of some question that Kleck might ask. Feel free to share this "killer question" with us. If it exists, of course.

I believe that it has already been explained here how Kleck's critique of Killias is erroneous.