---------------------------------------------------------------------- Open letter by Dr. Paul H. Blackman, Research Coordinator for NRA-ILA. NRA Official Journal 1/89. -----------------------------------------------------------------------  Dear sir:  By now, we are used to the New England Journal of Medicine's publication of small-scale studies related to firearms from which conclusions are drawn which are quantum leaps from the data, followed by announcements of  momentus "scientific" findings. These are regularly released to the press without the caveats which riddle the conclusory paragraphs, and often accompanied by an editorial calling attention to the findings. Generally, while they at least present a few interesting data, however meaningless, the studies misinterpret statistics, and ignore or belittle serious studies by criminologists.  The latest effort -- "Handgun Regulations, Crime, Assaults, and Homicide: A Tale of Two Cities," by J.H. Sloan, et al., with the accompanying  editorial, "Firearms Injuries: A Call for Science," by two employees of the Centers for Disease Control (November 10), however, is an insult to the intelligence of any serious scholar in any field and have so few data and so many flaws that I feel compelled to write at some length to call attention to various major and minor failings, in no particular order.  	1. The authors misleadingly cite Wright, et al. (Ref. 1) to  	support the statement that "some have argued that restricting 	access to handguns could substantially reduce our annual rate 	of homicide." Wright, et al., in fact studied and rejected that 	contention. 	 	2. The authors pretended that Vancouver and Seattle are very 	similar cities with similar economic circumstances, histories, 	demographic characteristics, and the like. In fact, the cities 	are very different with very different demographic characteristics 	which appear to explain completely the higher homicide rate in 	Seattle. Both cities are over three-forths non-Hispanic white 	and *the non-Hispanic white homicide rates are reported to be 	the same in Seattle and Vancouver*. It is the different back- 	grounds, problems, circumstances, and behaviors of the various 	ethnic minorities which explain the difference in homicide. 	 	3. The authors pretend they are evaluating Canada's gun law, 	compared to Washington State's. But they do not examine at all 	the situation in Vancouver prior to the gun law taking effect 	in 1978. As it happens, in the three years prior to that (1975- 	1977), Vancouver averaged 23 homicides per year, one-eighth 	involving handguns, (Ref. 2) and in the seven years of the NEJM 	article there were 29 homicides per year, one-eigth involving 	handguns. Surely even the medical profession recognizes that 	one must look to see the prior situation was before concluding 	that a change made a difference? Would a physician conclude that 	a patient was benefiting from eating oat bran muffin each day 	for seven years because his cholesterol level was 200 without 	at least seeing if it was 180 before he started the regimen? 	 	4. The authors pick two medium-sized cities to evaluate a national 	gun law. Nothing can be learned from such a tiny and arbitrarily 	selected sample. Seattle appears to have been selected because 	it was convienient for the authors rather than for any scientific 	reason. Would physicians call something a scientific study which 	involved one experimental subject and one dissimilar "control"? 	Had different arbitrarily selected cities been chosen, opposite 	"scientific" conclusions would follow: Vancouver's homicide 	rate *exceeds* that of such "wild west" cities in Texas as 	El Paso, Corpus Christi, Austen, and, in Colorado, Colorado 	Springs. (Ref. 3) 	 	5. The authors fail to clearly demonstrate that firearms or 	handguns "are far more commonly owned in Seattle than in 	Vancouver." They use two surrogate approaches in pretending 	to study the availability of firearms/handguns. The first is 	an apples-and-oranges effort to compare the number of carry 	permits in Seattle to the number of registered handguns in 	Vancouver. But the number clearly understates the number of 	handguns in Seattle, and counts primarily *protective* handgun 	owners. The second, however, tells nothing about the number 	of handguns in Vancouver, and counts *non-protective* handguns 	for the most part. Where is it difficult to obtain handguns 	legally for protection, registration figures are 	meaningless. There are 66,000 registered handguns in New York 	City (New York Daily News, Sept. 27, 1987). Comparing the two, 	that method suggests about 930 handguns per 100,000 population 	in New York City compared to 960 in Vancouver, meaning Vancouver 	has a greater "prevalence of weapons" than New York City. 	 	The second method of measuring gun density is "Cook's gun 	prevalence index, a previously validated measure of intercity 	differences." But the validation was by Cook of his own 	theory. (Ref. 4) Normally, second opinions are sought from a 	different doctor. More significantly, the Cook index is 	based on the average of the percentage of firearms involvement 	in suicide and homicide. So the authors are basically taking 	a measure of misuse. Unsurprisingly, gun misuse in homicide 	(42% in Seattle, 14% in Vancouver) is related to gun misuse in 	homicide plus suicide, divided by two (41% in Seattle, 12% in 	Vancouver). The authors are not measuring the relative avail- 	ability of firearms, or of handguns, in Seattle and 	Vancouver. 	 	6. The authors misstate the laws of both Washington and 	Canada. They neglect to mention the significant fact that 	Washington has a waiting period and background check prior to 	the purchase of a handgun, and that provisions exist in Canadian 	law for owning and carrying handguns for personal 	protection. The authors also make it appear that it is more 	difficult to get a handgun legally in Canada than is actually 	the case. 	 	7. The authors ignore all other factors which might explain 	the differences in crime rate, beyond some vague mention of the 	penalities provided by law and the roughest of estimates of  	clearence for one particular offense -- homicide involving a 	firearm. There is no measure of: the differences in the number 	of law enforcement officers; their aggressiveness in making 	arrests for gun law violations in the two jurisdictions; arrest 	rates for other offenses; conviction rates; actual sentences 	imposed for gun-related crimes, violent crimes without guns, 	or gun law violations; or incarceration rates. Whereas social 	scientists would attempt to measure and hold for such differences, 	the authors of the NEJM "tale of two cities" fail even to mention 	most factors related to crime control. 	 	8. The authors dismiss claims that handguns are an effective 	means for protection unless the criminal is killed. Such is not 	the case. Criminologists (Ref. 5-8) have found that almost 	650,000 Americans annually use handguns for protection from 	criminals, and that using a gun for protection reduces the 	liklihood that a crime -- rape, robbery, assault -- will be 	completed by the criminal and reduces the likelihood of injury 	to the victim. It is interesting, nonetheless, that the authors 	reported the same number (four) of civilian justifiable homicides 	without firearms in each city but that less restrictive Seattle 	accounted for 100% of the reported civilian justifiable homicides 	involving firearms. 	 	9. The Centers for Disease Control, which funded the "study," 	editorially praised the paper, (Ref. 9) saying it "applied 	scientific methods to examine a focus of contention betweeb 	advocates of stricter regulation of firearms, particularly 	handguns." There is nothing in the paper which could possibly 	be mistaken for "scientific methods" by a sociologists or 	criminologists. The Vancouver-Seattle "study" is the equivolent 	of testing an experimental drug to control hypertension by finding 	two ordinary-looking middle-class white males, one aged 25 	and the other 40, and without first taking their vital signs, 	administering the experimental drug to the 25-year-old while 	giving the 40-year-old a placebo, then taking their blood pressure 	and, on finding the younger man had a lower blood pressure,  	announcing in a "special article" a new medical breakthrough. 	It would be nice to think that such a "study" would neither be 	funded by the CDC or printed by the NEJM. 	 	Since the longstanding anti-gun biases of the NEJM and the CDC 	make them willing to present shoddy research as "scientific 	breakthroughs" in "special articles" and editorials relating 	to firearms, we are obligated to correct the record by notifying 	the news media and those with congressional and executive oversight 	over the activities of the Centers for Disease Control about 	the distortions contained in "Handgun Regulations, Crime, Assaults, 	and Homicides: A Tale of Two Cities" and "Firearm Injuries: A Call 	for Science." Clearly, all scientific standards go by the wayside 	whenever the CDC and the New England Journal of Medicine seize 	an opportunity to attack firearms ownership in America. 	 				REFERENCES  1. Wright JD, et al, *Weapons, crime and violence in America*: a literature review and research agenda, Washington, D.C.: Department of Justice, 1981.  2. Scarff E. *Evaluation of the Canadian gun control legislation*: final report. Ottawa: Ministry of the Solicitor General of Canada, 1983, p. 87.  3. Department of Justice, Federal Bureau of Investigation, *Crime in the United States*, 1987 (Uniform Crime Reports). Washington, D.C.: Government Printing Office, 1988  4. Cook PJ. *The role of firearms in violent crime*. In: Wolfgang M. Weiner NA, eds. *Criminal violence*, Beverly Hills, Calif.: Sage, 1982: 236-90, pp. 270-271.  5. Kleck G. *Crime control through the private use of armed force*. Social Problems 1988: 35:1-21.  6. Ziegenhagen EA, Brosnan D. *Victim responses to robbery and crime control policy*. Criminology. 1985: 23:675-695.  7. Lizotte AJ. *Determinants of completeing rape and assault*. Journal of Quantitative Criminology. 1986: 2:203-217.  8. Sayles SL, Kleck G. *Rape and resistance*. Paper at the American Society of Criminology convention, Chicago, 1988.  9. Mercy JA, Houk VN. *Firearm injuries: a call for science*.  NEJM: 319:1283-1285. ==========================================================================                               GUNS AND SPUTTER                             by James D. Wright           (from July 1989 issue of REASON, Free Minds & Free Markets)        Someone once wrote: "Statistics are like a bikini.  What they real is    suggestive, but what they conceal is vital."  The problem is demonstrated    by the most recent entry in a long line of scientific research purporting    to show a causal link between gun availability and homicide.  Funded by    the federal government and published last year in the New England Journal    of Medicine, the study compared homicide rates in Seattle and Vancouver and    suggested that a handgun ban "may reduce the rate of homicide in a     community."       The nine medical doctors who published "Handgun Regulations, Crime,    Assaults, and Homicide" essentially reasoned in three steps: (1) Despite    many historical, social, and demographic similarities, (2) Vancouver    has a markedly lower homicide rate (3) because its stricter gun regulations    make guns less available.  The second step in their reasoning seems    indisputable.  The overall homicide rate in Seattle (for the period    1980-86) was 11.3 per 100,000 popuation, compared with 6.9 in Vancouver.    Homicide is definitely more common in Seattle.  The question then becomes,    Why?       The authors present a believable although not entirely accurate case    to support the notion, as claimed in the third step of their reasoning,    that Vancouver's handgun regulations are much more stringent.  But their    evidence on the difference in gun *availabilty* is indirect and     unpersuasive; indeed, they acknowledge that direct evidence on the point    does not exist.  They offer two fragments of inferential data in support    of the claim that guns are more available in Seattle; but for all anybody    knows as a matter of empirical fact, the opposite could be true.  We    are therefore being asked, at the conclusion of the study, to believe that    a difference in gun availability explains the difference in homicide rates    when a difference in gun availability has not itself been established.       Indeed, the situation is even more troublesome.  The first of the two    indirect bits of evidence is a difference between the number of concealed-    weapons permits issued in Seattle and the number of restricted-weapons    permits issued in Vancouver.  Differences between the two cities in the    permit regulations render these two numbers strictly noncomparable. *     The second bit of evidence is "Cook's gun prevalence index," which stands *  at 41 percent for Seattle but only 12 percent for Vancouver.  Cook's index *  however, does not measure the relative prevalence of gun ownership in  *  various cities.  It measures gun misuse--it is an average of the percentage *  of homicides and suicides involving firearms. *     In the present case, the index shows only that in homicides and suicides, *  firearms are more likely to be used in Seatte than in Vancouver.  To take *  Cook's index as a measure of general firearms availability, it must be *  assumed that the proportional involvement of guns in homicides and suicides *  is directly related to their relative availability in the general  *  population.  But this is exactly what the authors are seeking to prove. To *  assume what one is seeking to prove, then to "prove" it on the basis of *  that assumption does ot constitute scientific evidence for anything.       Even if we were to grant, on the basis of no compelling evidence, that    guns are less common in Vancouver, we might still question what causes what.    The authors attribute Seattle's higher crime rate to a higher rate of gun    ownership.  But it might well be argued that low crime or homicide rates    reduce the motivation for average citizens to obtain guns--in other words,    that crime rates explain the variation in gun ownership, not vice versa.       In fact, it was once commonly argued that Great Britain's low rate of    violent crime was a function of that nation's strict gun laws and the     consequent low rate of gun ownership--until British researcher Colin     Greenwood found that Great Britain had enjoyed low rates of violent crime    for many decades before strict firearms controls were enacted.  To invoke    an ancient methodological saw, correlation is not cause.       Nor do the problems with this study end with its lack of direct data    on gun ownership.  The authors say Seattle and Vancouver are "similar in    many ways," implying that they differ mainly in gun availability, gun-law    stringency, and crime rates.  This is an evident attempt to establish    the ceteris paribus condition of a sound scientific analysis--that "all    else is equal" among things being compared. *     Clearly the two cities are similar in some ways, but a closer look  *  reveals differences in ways that are relevant to their respective crime *  or homicide rates.  The cities are closely matched in what percentage *  of their population is white (79 percent and 76 percent).  But Seattle *  is about 10 percent black, while Vancouver is less than 0.5 percent. *  Vancouver's minority population is overwhelmingly Asian.  So although the *  authors show that th two cities are approximately comparable on a half- *  dozen readily available demographic indicators, they have not shown *  that all potentially relevant sources of variation have been ruled out. *     In fact, the differences in racial compositions of the two cities is *  particularly relevant in light of the study's breakdown of homicide rates *  according to the race of the victim.  For the white majority, the homicide *  rates are nearly identical--6.2 per 100,000 in Seattle, 6.4 in Vancouver. *  The differing overall homicide rates in the two cities are therefore due *  entirely to vastly different rates among racial minorities.  For blacks, *  the observed difference in homicide rate is 36.6 to 9.5 and for Hispanics *  26.9 to 7.9.  (Methodoligical complexities render the Asian comparison *  problematic, but it too is higher in Seattle than in Vancouver.)  Racial *  minorities are much more likely to be the victims of homicide in Seattle *  than in Vancouver; the white majority is equally likely to be slain *  in either city.       Since the nearly 2:1 initial difference in homicide reates between the    cities is due exclusively to 3:1 or 4:1 differences between minority     groups, it is fair to ask why postulated difference in "gun availability"    (or gun-law strigency) would matter so dramatically to minorities but not    matter at all to whites.  Can differential gun availability explain why    blacks and Hispanics--but not whites--are so much more likely to be killed    in Seattle than in Vancouver?  (Studies in the United States, incidentally,    do not show large or consistent racial differences in gun ownership.)       Or are other explanations more plausible?  Could the disparity between    Canadian and American rates of poverty among racial minorities have     anything to do with it?  What are the relative rates of drug or alcohol     abuse?  Of homelessness among each cty's minority population?  (The city    of Seattle runs the largest shelter for homeless men west of the     Mississippi.)  Unemployment among young, central-city, nonwhite men in the    United States usually exceeds 40 percent.  What is the comparable Canadian    percentage?       The crucial point is that Canada and the United States differ in many    ways, as do cities and population subgroups with the two countries.  Absent    more detailed analysis, nearly any of these "many ways" might explain part    or all of the difference in homicide rates.  In gross comparisons such    as those between Seattle and Vancouver, all else is *not* equal. *     The authors of this study acknowledge that racial patterns in homicide *  result in a "complex picture."  They do not acknowledge that the ensuing *  complexities seriously undercut the main thrust of their argument.  They *  also acknowledge that "socio-economic status is probably an important *  confounding factor in our comparison," remarking further that "blacks    *  in Vancouver had a slightly higher mean income in 1981 than the rest of *  Vancouver's population."  Given the evidence presented in the article, *  it is possible that all of the difference in homicide rates between Seattle *  and Vancouver results from greater proverty among Seattle's racial *  minorities.  But the authors pay no further attention to this possibility, *  since "detailed information about household incomes according to race *  is not available for Vancouver."       The largely insurmountable methodological difficulties confronted in     gross comparative studies of this sort can be illustrated with as simple    example.  If one were to take all U.S. couties and compare them in terms    of (1) pervalence of gun ownership and (2) crime or homicide rates, one     would find an astonishing pattern: Counties with more guns have less crime.    Would one conclude from this evidence alone that guns actually reduce     crime?  Or would one insist that other variables also be taken into    account?  In this example, the "hidden variable" is city size: Guns are    more common in small towns and rural areas, whereas crime is a big-city    problem.  If researchers failed to anticipate this variable, or lacked the    appropriate data to examine its possible consequences, they coud be very    seriously misled.  In the study at hand, the authors matched two cities    for size but not for minority poverty rates or other hidden variables,    and their results are impossible to interpret.       In the editorial "Firearm Injuries: A Call for Science" accompanying    the study, two officials from the Centers for Disease Control lauded the    authors for applying "scientific methods" to a problem of grave public    heath significance.  But in attempting to draw causal conclusions from    nonexperimental research, the essence of scientific method is to anticipate    plausible alternative explanations for the results and try to rule them    out.  Absent such effort, the results may well seem scientific but are    little more than polemics masquerading as serious research.  That this    study is but one of a number of recent efforts--all employing practical    identical research designs and published in leading scientific journals--    is cause for further concern.     [James D. Wright is professor of sociology at Tulane University.  He has    researched extensively on the relationship of firearms and crime.]  Reason published monthly except combined August-September issue by the Reason Foundation, a nonprofit, tax-exempt organization.  Subscription rate: $24.00  per year.