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Private citizens
sometimes use their guns to scare off
trespassers and fend off assaults. Such
defensive gun uses (DGUs) are some-
times invoked as a measure of the
public benefits of private gun owner-
ship. On the basis of National Crime
Victimization Survey (NCVS) data, one
would conclude that defensive uses
are rare indeed, about 108,000 per
year. But other surveys yield far higher
estimates of the number of DGUs.
Most notable has been a much publi-
cized estimate of 2.5 million DGUs,
based on data from a 1994 telephone
survey conducted by Florida State
University professors Gary Kleck and
Mark Gertz.
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The 2.5 million figure
has been picked up by the press and
now appears regularly in newspaper
articles, letters to the editor, editorials,
and even Congressional Research Ser-
vice briefs for public policymakers.
The NSPOF survey is quite similar to
the Kleck and Gertz instrument and
provides a basis for replicating their
estimate. Each of the respondents in
the NSPOF was asked the question,
"Within the past 12 months, have you
yourself used a gun, even if it was not
fired, to protect yourself or someone
else, or for the protection of property at
home, work, or elsewhere?" Answers
in the affirmative were followed with
"How many different times did you use
a gun, even if it was not fired, to pro-
tect yourself or property in the past 12
months?" Negative answers to the first
DGU question were followed by "Have
you
ever
used a gun to defend yourself
or someone else?" (emphasis in origi-
nal). Each respondent who answered
yes to either of these DGU questions
was asked a sequence of 30 additional
questions concerning the most recent
defensive gun use in which the respond-
ent was involved, including the
respondent's actions with the gun, the
location and other circumstances of
the incident, and the respondent's re-
lationship to the perpetrator.
Forty-five respondents reported a de-
fensive gun use in 1994 against a per-
son (exhibit 7). Given the sampling
weights, these respondents constitute
1.6 percent of the sample and repre-
sent 3.1 million adults. Almost half of
these respondents reported multiple
DGUs during 1994, which provides
the basis for estimating the 1994 DGU
incidence at 23 million. This surpris-
ing figure is caused in part by a few
respondents reporting large numbers
of defensive gun uses during the year;
for example, one woman reported 52!


A somewhat more conservative NSPOF
estimate is shown in the column of ex-
hibit 7 that reflects the application of
the criteria used by Kleck and Gertz to
identify "genuine" defensive gun uses.
Respondents were excluded on the ba-
sis of the most recent DGU description
for any of the following reasons: the re-
spondent did not see a perpetrator; the
respondent could not state a specific
crime that was involved in the inci-
dent; or the respondent did not actu-
ally display the gun or mention it to
the perpetrator.
Applying those restrictions leaves 19
NSPOF respondents (0.8 percent of
the sample), representing 1.5 million
defensive users. This estimate is di-
rectly comparable to the well-known
estimate of Kleck and Gertz, shown in
the last column of exhibit 7. While the
NSPOF estimate is smaller, it is statis-
tically plausible that the difference is
due to sampling error. Inclusion of
multiple DGUs reported by half of the
19 NSPOF respondents increases the
estimate to 4.7 million DGUs.
Some troubling comparisons.
If
the DGU numbers are in the right
ballpark, millions of attempted as-
saults, thefts, and break-ins were
foiled by armed citizens during the 12-
month period. According to these re-
sults, guns are used far more often to
defend against crime than to perpe-
trate crime. (Firearms were used by
perpetrators in 1.07 million incidents
of violent crime in 1994, according to
NCVS data.)
Thus, it is of considerable interest and
importance to check the reasonable-
ness of the NSPOF estimates before
embracing them. Because respondents
were asked to describe only their most
recent defensive gun use, our compari-
sons are conservative, as they assume
only one defensive gun use per de-
fender. The results still suggest that
DGU estimates are far too high.
For example, in only a small fraction
of rape and robbery attempts do vic-
tims use guns in self-defense. It does
not make sense, then, that the NSPOF
estimate of the number of rapes in
which a woman defended herself with
a gun was more than the total number
of rapes estimated from NCVS (exhibit
8). For other crimes listed in exhibit 8,
the results are almost as absurd: the
NSPOF estimate of DGU robberies is
36 percent of all NCVS-estimated rob-
beries, while the NSPOF estimate of
DGU assaults is 19 percent of all ag-
gravated assaults. If those percentages
were close to accurate, crime would be
a risky business indeed!
NSPOF estimates also suggest that
130,000 criminals are wounded or
killed by civilian gun defenders. That
number also appears completely out of
line with other, more reliable statistics
on the number of gunshot cases.
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The evidence of bias in the DGU esti-
mates is even stronger when one re-
calls that the DGU estimates are
calculated using only the most re-
cently reported DGU incidents of
NSPOF respondents; as noted, about
half of the respondents who reported a
DGU indicated two or more in the pre-
ceding year. Although there are no de-
tails on the circumstances of those
additional DGUs, presumably they are
similar to the most recent case and
provide evidence for additional mil-
lions of violent crimes foiled and per-
petrators shot.