Monday, January 09, 2006

Response to Questioning the Plausibility of Helena Findings from a Study Author

I received the following response, written by one of the authors of the original Helena study, to my questioning of the plausibility of the claim that the Helena smoking ban reduced heart attack admissions by 40% within six months.

How to Protect the Credibility of Secondhand Smoke Science from the Threats Posed by Michael Siegel's Ill Informed Criticisms of Helena/Pueblo

Michael Siegel has put out another blog expressing concern that the media is questioning the credibility of the evidence that there are rapid drops in heart attacks when smokefree laws go into force. He is, of course, one of the main reasons for this questioning. The two main sources of criticism are Michael Siegel and Jacob Sullum from the Reason Foundation (which has a history of tobacco industry funding). While Siegel and Sullum (and, to a lesser extent, Ken Warner, who agrees that there is an effect, but thinks thinks that the OBSERVED changes are too big to be "mathematically possible") have all said they don't believe the evidence, none has presented a plausible alternative explanation for the observed evidence.

The fact that there was a 13% drop in heart attacks in New York City also provides more evidence for a large immediate effect of eliminating exposure to SHS. (One would expect a smaller change in NYC than in isolated places like Helena or Pueblo because not all people covered by the ordinance would be hospitalized in NYC and vice versa. In addition, there were some earlier ordinances in some surrounding jurisdictions, which would "smear out" the effect in time.)

We have addressed these issues (except the NYC information, which came later) at .

The Rest of the Story

This is an interesting response, because rather than address the specific criticism, which is that the Helena claim of a 40% drop in heart attacks due to 6 months of a smoking ban is implausible (given that if all smoking were eliminated completely, there could be, at most, a 50% reduction in heart attacks based on the epidemiologic data), the response instead tries to discredit the messenger, first by suggesting that he is ignorant of something without mentioning what it is that he is ignorant of, and second by trying to associate him, through a chain of links, to the tobacco industry.

The only possible response that would adequately address my commentary is one which explained why a 40% drop in heart attacks due to a smoking ban is plausible, in light of the epidemiologic data which suggest that no more than a 50% reduction in heart attacks is possible even if all smoking and secondhand smoke were to be completely eliminated.

In other words, what I am suggesting is that it is mathematically impossible for the smoking ban to have caused a 40% reduction in heart attacks.

The way to deal with such an argument would be to provide some rationale, or some reason, why it is not in fact mathematically impossible, which the response (as well as the eletters) fails to do.

As far as offering a plausible alternative explanation for the observed findings - I have already offered one. I believe that the findings could well be due to random variation in the heart attack trend. I have already explained why this alternative explanation is entirely consistent with all of the data and findings that have been presented.

But it is important also to recognize that if the problem is that the study findings are implausible, then the burden is not on the reviewer to supply an alternative explanation for the findings; the burden is on the one making the claims to explain why the results are plausible.

It's kind of like suggesting that if I question the claim that the flying spaghetti monster is responsible for the creation of the universe because I don't think that it's plausible that a flying spaghetti monster created the universe, I must supply an alternative explanation for the creation of the universe or my criticism of the flying spaghetti monster theory is not valid. Hardly.

Let me reiterate that I'm not questioning the premise that a smoking ban will reduce heart disease, including incidence of heart attacks. I'm just pointing out that a 40% drop in heart attacks due to a smoking ban is completely implausible, and mathematically impossible.

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