From: bb063@cleveland.Freenet.Edu (Christopher J. Crobaugh)
Newsgroups: talk.politics.guns
Subject: re: Effectiveness of gun control
Date: 28 Dec 1992 23:57:29 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: slc10.ins.cwru.edu


Dean Alaska (dean@vexcel.com) posts, in message 47788, the 
article from the New England Journal of Medicine that purports 
that Washington DC'virtual gun ban CAUSED a drop in gun crime
in DC. I re-post here, for the benefit of all, Dean Payne's
debunking of that article; I have already Emailed it to
Dean Alaska (here's hoping he gets it).

Subject: More NEJM commentary
Date: Wed Dec 11 09:34:44 1991

This is from: Dean Payne <deanp@lsid.hp.com>

The December 5 issue of the New England Journal of Medicine has a
Special Article titled "Effects of Restrictive Licensing of
Handguns on Homicide and Suicide in the District of Columbia" by
Colin Loftin and others.  (NEJM, Vol. 325, Num. 23, p. 1615-20).

Last week, I gave my first reactions to this study.  Here is a more
detailed commentary, based on more concrete population and homicide
figures.  This is still preliminary, as I am missing some 1983
numbers.

The core data of Loftin's study shows that the average monthly
number of gun-related homicides and suicides dropped significantly
in DC after it imposed its 1976 handgun ban, whereas non-gun deaths
in DC and gun and non-gun deaths in the surrounding MD/VA
communities did not drop.

Let me restate Loftin's data, but combining gun and non-gun deaths: 
                  
                            mean numbers of deaths per month:     
                      before         after         change Homicide
District of Columbia    20.3           16.7          -18%   
Maryland / Virginia      8.8            9.1          + 3% Suicide 
District of Columbia     7.0            6.0          -14%   
Maryland / Virginia     19.1           20.0          + 5%

Note that these are deaths per month, not per-capita rates.  The
study mentioned population only to assure us that there were no
significant changes in the age distribution of either group.  The
report report did not mention actual populations or any population
growth or shrinkage.

I averaged the populations from annual FBI and Census Bureau
reports(*), and found significant population changes of the study
areas:

                            mean population:
                           before         after         change
District of Columbia         740,800        639,900     -14%
Maryland / Virginia        2,197,400      2,587,900     +18%

I also added up the homicides reported by the FBI UCR.  My pre-ban
numbers matched well with Loftin's figures, but the post-ban
numbers show a large discrepancy(*).  My count shows about 100
fewer homicides within DC and about 80 more in MD/VA than are
evident in Loftin's numbers.  Here are both my preliminary count
and Loftin's numbers, but expressed as per-capita rates:

                            mean annual rates, per 100k residents: 
                          before         after         change My
homicide count 
District of Columbia     32.9           29.9          - 9%   
Maryland and Virginia     4.8            4.5          - 6%

Loftin's homicide rates 
District of Columbia     32.8           31.3          - 5%   
Maryland and Virginia     4.8            4.2          -12%

Loftin's suicide rates 
District of Columbia     11.3           11.3          - 1%   
Maryland and Virginia    10.4            9.3          -11%

Loftin suggests that DC's handgun ban saved 47 lives per year (3.3
gun-related homicides and 0.6 gun-related suicides per month). 
This view collapses when per-capita rates are examined.  Some lives
in DC were saved by the overall death rate decline visible in both
groups, but many lives were saved simply because many people moved
out of the District of Columbia.  Body counts in neighboring areas
didn't drop simply because the declining death rate was outpaced by
a rapidly growing population.

Using my count, the reduction in death rates that could possibly be
attributed to the handgun ban (DC experienced a 3% better homicide
reduction than did MD/VA) is too small to be statistically
significant. Using Loftin's rates, that difference vanishes
altogether, because DC was less successful than its neighbors at
reducing its death rates. 

Loftin's dataset ends in 1987, prior to the murder explosion that
has made Washington DC the Murder Capital of the United States.  I
haven't yet recomputed these charts to reflect that data, but
remain surprised that any city that is experiencing a doubling of
its already horrendous homicide rate could simultaneously be
heralded as a successful example of restrictive handgun control.


========================  Important notes===========================

(*) I don't have 1983 UCR data yet, so that year is left out of my
MD/VA data.  DC-city data for that year is taken from the 1984 UCR.

For Loftin's study, 'before' is Jan 1968 to Sep 1976, 'after' is
Oct 1976 to Dec 1987.  Because my data is annual, not monthly, I
counted all of 1976 as 'before'.  This ought not be significant,
especially in light of the legal battles that suspended the ban
from Dec 1976 to Feb 1977.

The portions of Maryland and Virginia used for this comparison are
the communities neighboring DC that make up the Washington DC-
Maryland-Virginia Standard Metropolitan Statistical Area, exclusive
of DC itself. This is the same area listed as the Washington DC MSA
in Appendix IV of recent FBI Uniform Crime Reports (UCR), or in
Table 5 of older editions.
In all cases, my Maryland and Virginia figures are derived by
subtracting the DC-city figures from the DC-MSA figures.

All DC-MSA populations are from the UCR.  DC-city populations have
been listed in the UCR only since 1979.  Census Bureau data (from
Statistical Abstracts of the U.S.) are used for earlier years. 
Different editions of the Statistical Abstracts display as many as
three different population estimates for any given year.


I will post my entire set of raw data after filling in the missing
1983 figures.

Dean Payne 
deanp@lsid.hp.com



-- 
bb063@Cleveland.Freenet.Edu  Chris Crobaugh - (216) 327-6655 (V)
"Those who would sacrifice essential liberties for a little 
temporary safety deserve neither liberty nor safety." B. Franklin