Alternatively, a respondent making up a DGU, or describing a friend's
DGU as if it happened to someone in the respondent's household will
tend to make him or herself the defensive gun user.
Joel Friedman writes:
While I do not disagree, your estimate of 70% / 15% is just that an
estimate. It is also possible to argue that the numbers could be
50%/ 25% or 60 / 25% ? If this is not correct, please enlighten me
as to why the 70% / 15% is more correct?
Out of each 100 reported DGUs, 85 involved the respondent, and 15 some
other member of the household. The real numbers must be equal. Kleck
believes that the true numbers are 85 and 85, that is, the respondents
concealed 70 DGUs involving other household members. Alternatively
the true numbers could be 15 and 15, that is, the respondents made up
(wholly or partially) 70 DGUs involving themselves. This one factor
alone makes an enormous difference to your estimate of DGUs: 170 vs
30, a factor of almost six.
It may be that of
those that reported a DGU to Kleck, 70% made it up or changed the user
to him or herself. That would leave 15% where the respondent was the
user and 15% where it was someone else in the household.
There is a similar anomaly with when the incident occured. You would
expect 20% of the DGUs to have occured in any one of the five years.
But twice as many (40%) occured within the last year.
Seems likely, but doesn't Kleck himself discuss this phenomena as well
as the telescoping phenomena as the reason for this? Are not his
explanations suitable to the discussion?
Telescoping that inflated the estimate by 100% could certainly cause
such an anomaly. Kleck believes that the overestimate due to
telescoping was no more than 21%. Another possible explanation: If
you are making up a DGU, or perhaps changing the time of a real DGU to
fit into the five year period that Kleck asks about you might randomly
answer yes or no to the question about whether it was during the past
year. If so, and if all the DGUs reported were made up, then you would
see 50% of the DGUs reported as occurring in the past year. The fact
that the number was neither 50% nor 20%, but 40% suggests that we are
seeing some mixture of false and true reports of DGU.
Professor Volokh commented on cuing and the NCVS of DGUs. Cuing is
mentioned quite a lot in the BJS report on the NCVS redesign.
Does anyone know what estimate you get for DGUs from the 93
(redesigned) NCVS? Since the redesign turned up more crime, it should
be a bit higher than previous estimates. One of the stated objectives
of the NCVS is to measure victim's response to crime and the people
who did the redesign seemed well aware of the need for multiple
cueing, so I'd be a bit reluctant to assume that messed up somehow and
produced an instrument that gave wildly incorrect estimates of the
responses to crime.
Discussion about correlation between gun ownership and crime: This
arose from my statement that Kleck's survey implied that 16% of
burglaries resulted in a DGU. (Obtained by dividing the number of DGU
vs burglary given by his survey by the total number of burglaries
given by his survey.) I went on to suggest that this implied that at
least 32% of US burglaries would have to have someone at home. Mark
Gibson argued that the number might be smaller if burglaries were
concentrated in gun owning households. Pim van Meurs argued that this
was not true since crime and gun ownership were uncorrelated in
general. I have to disagree here. AFTER CONTROLLING FOR OTHER
FACTORS crime and gun ownership were uncorrelated. If you are
interested in the question of whether general gun ownership causes or
prevents crime, or if actual (as opposed to perceived) crime rates
cause gun ownership, then this is the appropriate measure. However,
we are want to know if 50% of burglaries are of gun-owning
households. In this case we are just interested in the univariate
correlation. Bordua (in a county level study of Illinois) found that
crime was (quite strongly) negatively correlated with gun ownership in
his univariate analysis. Consequently, it would seem that less than
50% of burglaries were of gun-owning households and the 32% figure a
very conservative underestimate. It doesn't seem likely that all
burglars would seek a confrontation with a gun-toting resident so the
true number would be quite a bit more than 32%.