Response to Teret |
This response was written by John Lott and webbed by David Friedman. Lott is responsible for contents; Friedman for formatting.
John Lott's Response to Stephen Teret's Critical Commentary on a Paper by Lott and Mustard
Claim #1: "The Study
uses incorrect and discredited methology"
a) The use of the
arrest rates in explaining crime rates
Teret provides a very biased reading of the
National Academy of Sciences report. For example, Vanaele (p.
281) concluded that: "the negative relationship between the
crime rate and the probability of imprisonment and between the
crime rate and the time served is not spurious." The
sociologists on the panel were more cautious but still concluded
(pp. 4 and 7) that, "Taken as a whole, the evidence
consistently finds a negative association between crime rates and
the risks of apprehension, conviction or imprisonment. . . . the
evidence certainly favors a proposition supporting deterrence
more than it favors one asserting that deterrence is
absent."
I think that there are also important theoretical reasons for
including variables like the arrest and conviction rates as well
as prison sentence lengths. Prior to my work none of the papers
on gun control had attempted to account for the impact of these
factors on the crime rate. In any case, the original paper and my
book also reported the results with the arrest rates excluded.
Even other critics such as Black and Nagin have claimed (December
6, 1996, p. 5) that: "The absence or presence of the arrest
ratio has little impact on the coefficient estimates in the
model."
b) "The
reductions in violent crime that the authors attribute to the
laws may simply be a commonly-observed downward drift in crime
rates toward some long-term average level."
To illustrate that the results are not
merely due to the "normal" ups and downs for crime, the
accompanying figure shows the pattern of violent crime before and
after the adoption of the shall-issue laws.1 The
declines not only begin right when the concealed-handgun laws
pass, but the crime rates end up well below what they were prior
to the law.
The original study as well as the book also included not only individual state and county time trends (p. 25, fn. 53 and pp. 34-37), but also a separate variable for each individual year to allow for any possible pattern in national crime rate trends over the 16 years studied in the original paper and 18 years studied in the book. In addition, different crime rates to explain the changes over time in the crime rates studied (pp. 31-34). Given the high correlation over time between different violent crime rates or between different property crime rates, this picks up most crime cycles.
Claim #2: "The
Study's results depart from well-established criminologic theory
and facts about crime."
a) The strongest effects should
be for robbery
I have two responses. First, as anyone who has carefully reads my
work will know, it is simply not true that the results show
"little or no effect on robbery rates." Whether the
effect was greater for robbery or other violent crimes depends on
whether one simply compares the mean crime rates before and after
the laws (in which case the effect is relatively small for
robbery) or compares the slopes before and after the law (in
which case the effect for robbery is the largest).
Second, it is not clear that robbery should exhibit the largest
impacts primarily because "robbery" encompasses many
crimes that are not street robberies. For instance, we do not
expect bank or residential robberies to decrease, and, in fact,
they could even rise. Allowing law-abiding citizens to carry
concealed handguns makes street robberies more difficult, and
thus may make other crimes like residential robbery relatively
more attractive. Yet, not only is it possible that these two
different components of robbery move in opposite directions, but
to rank some of these different crimes one requires information
on how sensitive different types of criminals are to the
increased threat.
Making claims about what will happen to different types of
violent crimes is much more difficult than predicting the
relative differences between, say, crimes where criminals have no
contact with victims and those crimes where they do. Though even
here some of these questions cannot be settled a priori.
For example, it is possible that when violent crimes decline more
people feel free to walk around in neighborhoods, which implies
that they are more likely to observe the illegal actions of
strangers. Criminals who commit violent crimes are also likely to
commit some property crimes, and anything that can make an area
unattractive to them will reduce both types of crime.
Claim #3: "The Study
does not account for the effects of other important gun
laws."
This is simply wrong. Both the original paper
and the book account for a wide array of different gun laws:
state waiting periods, the length of state waiting periods, state
background checks, the Brady Law, and penalties for using guns in
the commission of crime. Indeed, my work is the first attempt to
provide systematic national data on these questions. When one
looks at these other gun laws there is no evidence that they
reduce violent crime rates. If anything, there is some evidence
that the Brady Law slightly increased rape and aggravated assault
rates because the waiting period makes it difficult for a few
people to quickly obtain a gun for self-defense.
All the laws mentioned by Teret were controlled for in both
pieces.
Claim #4: "Knowing the
exact date that each `shall issue' law took effect is critically
important to measuring its impact -- yet the study includes some
errors in these dates."
I relied on a paper published in the Tennessee Law Review (Spring
1995) by Clayton Cramer and David Kopel to determine when
different states adopted shall issue laws. A separate Nexis data
base search was also conducted to determine the exact date of
adoption.
Because of different interpretations over
whether a particular law constituted a shall issue law, the
results were tested to see whether defining Maine and Virginia as
shall issue states made a difference and it did not (in the
original paper see p. 12, fn. 34 and p. 19, fn. 49 and in my book
see p. 201, fn. 5).
In any case, I agree with Cramer and Kopel's
classification of state laws. Virginia's 1988 law explicitly uses
the term "shall-issue," and, with the exception of
three counties, the state followed that rule.
Claim #5: "The
study does not consistently define what it is evaluating."
Again we followed Cramer and Kopel in defining
state laws. However, how Connecticut and Alabama adopted their
laws decades before the sample period [1977 to 1994] and thus
were not involved in any of the before-and-after comparisons of
shall issue laws that I focused on.
For a more complete response to my critics, please see Chapter 7 in my newly released book More Guns, Less Crime: Understanding Crime and Gun Control Laws (University of Chicago Press, 1998).
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