Jon Buck said:
NCS didn't do a very good job of asking; they only asked about
defensive weapon use after the respondent answered positively to
having been a victim of a crime.
Right, so cases where someone whipped out a gun without being
threatened with violence weren't counted.
Kleck makes this criticism of the NCS (in "Point Blank", if I
remember correctly). This leaves out the case of successful
self-defense, in which the intended victim was not victimized
because they used a gun in self-defense;
No it doesn't. Such a person is still a victim of the crime of
attempted robbery, or assault, or attempted whatever.
obviously, most of these people would have answered negatively to
the question "Have you been a victim of a crime?"
Since NCS does not ask this question, this point is irrelevant.
You have misunderstood Kleck's criticism. He is arguing that NCS
undercounts crimes such as domestic assaults and therefore undercounts
defensive gun uses in such situations. A valid criticism, but the
undercount would have to be truly vast to account for the discrepancy
between the 80,000 NCS derived count of defensive gun uses and Kleck's
2.5M. Nor is there any evidence that NCS significantly undercounts
burglaries, so it does not account for the factor of 28 discrepancy
above.
Read the article again; Kleck gives 2,500,000 as the upper bound for
self-defense uses, and 800,000 as the lower bound. Obviously, the
real number is probably somewhere in between. The same criticism of
the NCS figure applies here, too; robberies prevented by with-gun
self-defense are likely to go undiscovered using their questioning
methodology.
NCS asks: "Did anyone try to rob you?" Are successful defenders going
to say "no"?
Point the first: I don't think Kleck's 15% number is all that
accurate, since it is derived by dividing gun deaths into gun
woundings, and gun woundings are likely to be underreported,
especially minor ones received by criminals shot at by their victims,
which is what we are talking about.
Sure, it is possible that the correct figure is, say, 10%. It would
have to be 1% to explain the discrepancy, though, and this is just not
believable.
Point the second: even
police officers involved in shootings tend to over-report woundings of
the people they shot; I see no reason why a civilian poll would be any
different. Note that some of Kleck's other data suggests that only
1-2% of self-defense uses involve killing or wounding the attacker.
This was computed by taking Kleck's estimate of 1500-2800 justifiable
with-gun homicides, and applying the 15% fatality rate to get
9000-17000 woundings and dividing by his estimate of 1M self-defense
uses. Since his estimate of self-defense uses was an input to the
calculation, we cannot use this figure to cross check the validity of
his estimate of defense uses.
Running your same calculations with the two percent number yields 7500
justifiable with-gun homicides, which is still high but closer to a
realistic number. Using Kleck's old figure of 1.2 million
self-defenses (still within the range he is claiming), and the two
percent figure, we get 3600 justifiable homicides, which is much more
reasonable than 30,000, and closer to the 1,500 to 3,000 number
claimed by Kleck and others.
Not surprising: This calculation boils down to:
3000*.15*1.2M
-------------
.15*1M
It would have come out exactly if you had used Kleck's original 1M
estimate.