Kleck's DGU estimate fails cross checks of validity

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 killings
Wright and Rossi's survey of criminals
NEISS counts of gunshot wounds
NCVS counts of burglaries and violent crimes
UCR counts of burglaries and violent crimes
NCVS counts of DGUs
Dade county study of gun use by CCW holders.
Kellermann's Atlanta study of gun use against intruders.
NCVS and UCR counts of gun crimes

His data also contains anomalously high percentages of defences by the
respondent and by women.

The only thing that it agrees with are other surveys which are just as
vulnerable to fabrications by a small percentage of respondents.

As for the NSPOF survey, it has similar problems. Cook notes that
"almost half the incidents appear to contain some internal
inconsistency, or otherwise do not make sense."

Guns can be used against criminals perceived to be
using guns (roughly one million such crimes would
be projected lately from NCVS)

One million? But in his paper Kleck gives 550,000 as a "generous"
estimate. Is the NCVS right and Kleck wrong?

and against criminals
not perceived to be using guns, and thus can easily
outnumber gun-related crimes.

Have you considered the possibility that an armed criminal might
encounter an unarmed victim? Some folks have even suggested that they
might seek such victims out.

And Kleck would be the
first to note that the various breakdowns --- say 18%
of protective gun use --- are less reliable than the
overall figure,

A 95% confidence interval is 300,000 to 600,000. The statistical
reliability of this figure is similar to that of the Hart poll and
much more than that of the Mauser poll. It is odd that Kleck has not
discounted these estimates too.

In any case, even if we use the low end of the interval and the NCVS
estimate of criminal gun use instead of the Kleck one, we still find
the unlikely estimate that 30% of gun crimes involve the victim
pulling a gun on the perp.

NCVS remains the sport, and understandably since it's
the survey not aimed at measuring protective use of
anything.

This is untrue. The questions have been posted here and it is quite
clear that are interested in finding out what crime victims do for
protection. Kleck even uses it for that purpose.

What is true is that most of the surveys that agree with Kleck were
not designed for measuring protective uses. It is odd that you do not
discount these surveys because of this.

I don't think Killias and others were afraid of one
particular "killer question" so much as a series of
questions regarding the limitations of the studies on
which they would be relying.

OK, then share this series of questions with us. If such a series of
questions exists then you and Kleck would surely want to give it wide
publicity.

I don't know why Killias and some other anti-gun researcher bowed
out, but they should have known in advance that testimony would
involve a trip to Canada, but may not have known in advance that it
would involve Kleck's aid in the crossexamination to follow any
testimony. Why, after all, provide an affidavit for submission if
that affidavit cannot be submitted unless in-person testimony also
occurs?

That isn't the way things worked when I submitted an affidavit as an
expert witness to a court. I was told that I only needed to appear if
the other side wanted to cross examine me. Nor was the court date
scheduled for my convenience.

Incidentally, using an unpublished CDC study involving
36 generally affluent nations, with gun use in suicide
as the surrogate measure for gun availability, Kleck's
reanalysis indicates that with or without the U.S.
excluded, "there is no significant (at the 5% level)
association between gun ownership levels and the total
homicide rate in the largest sample of nations
available to study this topic."

Ahem. What he probably found was that there was no significant
correlation between the gun suicide rate and the the total homicide
rate. That's also true for Killias' data set. But if you use a
survey based measure of gun ownership as Killias did, you do find some
significant correlations.

That is, Kleck got a different result because he used a surrogate
measure rather than a direct one.

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