Fabrication of DGUs

John Briggs writes:

[Calculation of number of justifiable shootings deleted]
This would suggest 15,000 to
20,000 civilian justifiable woundings or 17,500 to 22,500 incidents in
which a civilian shot and hit an assailant.

Kleck does a similar calculation in “Point Blank” to get an estimate
of 10,000 to 20,000.

For reasons I allude to below I am inclined to believe that civilian DGUs
would be likely to result in a significantly lower killed-to-wounded ratio
than would criminal gun use. The 10% to 15% lethality ratio of gunshots may
lump together much higher kill-ratio criminal shootings intended to kill
with a much lower lethality ratio for civilian DGUs that would, I think,
more often include semi-warning shots likely to wound rather than kill.
Civilian DGUs do not have as their specific intent the killing of their
target so I am comfortable with the higher figure for woundings.

I think you’ll find that most criminal shootings are not
unambiguous attempts to kill (they generally do not finish the victim
off with a head shot at point blank range.) Some criminal shootings
are deliberate woundings. A large number of criminal shootings are
“drive-bys” — fired from long range and more likely to hit an
extremity than a self-defence shooting at close range. These factors
suggest that defensive shootings would be more lethal than criminal ones.

On the other hand, criminal shootings include some execution style
shootings, and you would expect that a self-dence shooter would be
more likely to call an ambulance. These factors suggest that
defensive shootings would be less lethal than criminal ones.

Overall, I don’t think you can come to a conclusion either way.

And, now for an inchoate thought: would not the propensity of braggarts to
fabricate DGUs be immune to telescoping and forgetfulness, unlike honest
respondents who would be depending on memories of actual events? If I am
correct in recalling that Kleck’s five-year data suggested only 800,000
DGUs, this substantial fall-off compared to the 2,500,000 DGUs based on
one-year positives seems to argue against fabrications as a significant
factor since there seems no reason that braggarts would prefer to fabricate
DGUs only in the one-year time period. Their influence would seem to be
substantially outweighed by honest (if not always accurate) respondents
whose recall would be subject to the conflicting factors of forgetfulness
in the long run and telescoping in the short.

The enormous difference between 800,000 (5 year recall, houshold DGUs)
and 2.5M (1 year recall, personal DGUs) is in fact string evidence
that there is some fabricating going on. Suppose you have made up a
DGU. Now Kleck asks you for details. “Was it within the past year?”
You answer randomly. So, you would expect about 50% of the fabricated
DGUs to occur in the past year. On the other hand, a real DGU would
be equally likely to fall into any of the five years and you would
expect about 20% to occur in the past year. In fact Kleck found 40%
said that it had occured in the past year, which suggests that there
is more fabricating than truth-telling going on. Because 40% is twice
20%, you get a factor of two difference in the estimate depending on
whether you use a 5 year recall or a one year recall. Kleck
explanation for this disrepency is recall failure – that is, half of
DG users forget the incident after a couple of years.

In trying to resolve the discrepancies between Kleck and the NCVS regarding
the percentage of “shots-fired” incidents I wonder if the differences lie,
in part, in the the focus of the latter on commission of a crime and some
sort of “legal” victimization status for the respondent. Perhaps the survey
process suppresses reports of numerous actual but borderline cases. The
NCVS respondents were, perhaps, much farther along in the crime
victimization process (so they were more obviously in danger and prompted
to shoot) whereas Kleck’s respondents include not only NCVS types but, say,
the female apartment dweller who refers to her handgun to send a persistent
stranger away from her door.

Kleck take pains to only count DGUs against actual crimes. I suppose
it is possible for this sort of incident to be included in Kleck’s
study if the respondent lied and said (for example) that the the
stranger tried to break in. (Presumably to make her actions seem more
reasonable. )

Furthermore, we don’t know B that well either. Kleck gives figures
of 37% for police and 18% for criminals (p173), but it might be
different for civilian DGUs. So, I’ll use both NCVS and the Kleck
survey to estimate B and see if the results are reasonable.

NCVS: A=0.4, so B=(10,000 to 20,000)/(0.4×80,000)=30 to 60%
Kleck: A=0.16 to 0.24, so B=(10,000 to 20,000) /((0.16 to 0.24)x2,500,000) = 2 to 5%

The top of the NCVS range for B seems rather high, but 30% seems like
reasonable number for B. Kleck’s survey gives numbers for B that are
way too low.

But the reasonableness of the 30% figure lies (only?) in the fact that it
is between the police 37% and the criminal 18%, yes? And the
unreasonableness of Kleck’s 2% to 5% derives (only?) from the fact that it
is so much lower than the criminals’ 18%, yes? Actually, it derives partly
from use of Kleck’s one-year-data estimate rather than his five-year
estimate. Preliminarily he suggested the longer-term data would give an
estimate of 800,000 DGUs each year but he preferred the one-year figure
because he felt forgetfulness was more of a problem than telescoping. Does
the final published version note the lower five-year estimate?

Afraid not. The lowest estimate he has is 1.2M, and it’s clear that he
regards the 2.5M one as best.

plug in 800,000 in place of 2,500,000 we get:

Kleck (against his will): B = 6.5% to 15.6%

I realize his 2,500,000 number gets the publicity and, apparently, he
considers it the better of the two numbers but is there any data on the
relative impacts of forgetfulness vs. telescoping to support his preference
for the one-year data?

He cites some data that suggests that telescoping would make no more
than a 20% difference. So the furthest you can go here is to get up
to almost 6%, whiich still seems unlikely.

In any event, your calculation should prompt us to wonder how civilian DGUs
ought to compare with police and criminal “success” rates. If the
inclinations of the civilian and the characteristics of his situation are
markedly different from those of police and criminals we might well find
that the percentage of situations in which a civilian “shots-fired”
incident resulted in a “hits-made” incident differs greatly from the
performance of police and criminals.

For example, a police officer is under a duty to stay engaged with a
criminal to apprehend him even if he flees and even at the risk of
prolonging or re-starting an exchange of gunfire. A civilian, in contrast,
would count it a success either to prompt his assailant to flee or to
disrupt his assailant’s attack sufficiently to allow himself to retreat.
Civilian DGUs ought to involve fewer shots, on average.

Not necessarily. The attacker is probably more motivated to attack
his victim than to fight third parties (like police).

The general
inaccuracy of gunfire under stress suggests to me that there would be many
more short exchanges of gunfire, characteristic of a civilian DGU, that
resulted in no one getting hurt than there would be with police against
criminal gunfire. A criminal’s use of gunfire would also, I think, be
significantly more likely to result in his target getting hit because the
criminal more often specifically wants his victim dead either because that
is the sole purpose of the shooting or because he fears retaliation from
his victim or because he wishes to leave no witnesses to his “main” crime.
He is less likely to quit shooting until he hits his victim or he runs out
of ammunition. These factors would tend to drive the criminal B ratio above
that of the civilian.

On the other hand criminal shootings are more likely to be at long
range where the chance of shootings are less.

While I’m here, this is my estimate of the number of DGU-related

The NEISS estimates 60k Assault/legal intervention nonfatal firearm
injuries treated in hospitals. According to the NCVS about 90% of
those wounded in this way get hospital treatment, so there are roughly
70k such woundings each year. Add in 18k deaths and I estimate about
90k assault/legal intervention shootings altogether. Using the data
from Table 4.2 (on Civilian Legal Defensive Homicides) as Kleck does,
about 10-13% of the woundings will be self-defence, or 9k-12k, i.e
roughly 10,000.