beneficial high-density lipoprotein (HDL) cholesterol.
I had already seen that French Paradox broadcast. As a matter of fact, I had watched your
French Paradox story when it was first broadcast on 5Nov95, and even while watching it I
had immediately recognized that your conclusion attributing longer life to wine drinking
was unjustified, and that you were causing harm in passing this conclusion along to a
large audience almost all of whom would accept it as true. At bottom, then, I see
little difference between your French Paradox story of 5Nov95 and your Ugly Face of
Freedom story of 23Oct94 - in each case, you ventured beyond your depth, giving
superficial judgments on topics that you were unqualified to speak on, discussing
questions that your education had given you no grounding in, and causing damage because
your conclusions proved to be false.
In the case of the Ugly Face of Freedom, the number of your errors was large, and the
amount of data that needed to be examined to demonstrate your errors was large as well,
as can be seen by the length of my rebuttal The Ugly Face of 60 Minutes. In the case of
the French Paradox, however, you make only one fundamental error which is to fail to
grasp the difference between experimental and correlational data - and my demonstration
of your error can compactly be contained within the present letter.
The reason that I am able to assert with some confidence that your conclusion that wine
drinking increases longevity is unjustified is as follows. I have a Ph.D. in
experimental psychology from Stanford, I taught in the Department of Psychology at the
University of Western Ontario for eleven years, and my teaching and my interests fell
largely into the areas of statistics, research methodology, and data interpretation.
Everyone with expertise in scientific method will agree with me that your conclusion in
The French Paradox was unwarranted. It is not necessary to read the original research
papers on which you rely to arrive at this same judgment - even the brief review of the
research data in your broadcast, even the briefer review of your broadcast in the Kim
Marcus quotations above - is enough for someone who has studied scientific method to see
that you were wrong. Below is my explanation.
The French Paradox Research
Cannot Have Been Experimental
There are two ways in which data relating wine consumption to longevity could have been
gathered - either in an experiment, or in a correlational study. If the data had been
gathered in an experiment, then it would have been done something like this. A number
of subjects (by which I mean human experimental subjects) would have been randomly
assigned to groups, let us say 11 different groups. The benefit of random assignment is
that it guarantees that the subjects in each group are initially equivalent in every
conceivable respect - equivalent in male-female ratio, in age, in health, in income, in
diet, in smoking, in drug use, and so on. That is the magic of random assignment, and
we cannot pause to discuss it - you will have to take my word for it.
To groups that enjoy pre-treatment equality, the experimenter administers his treatment.
After constituting his random groups, the experimenter would require the subjects in
each group to drink different volumes of wine each day over many years - let us say over
the course of 30 years. Subjects assigned to the zero-glass group would be required to
drink no wine. Subjects assigned to the 1-glass group would be required to drink one
glass of wine each day. Subjects assigned to the 2-glass group would be required to
drink two glasses of wine each day. And so on up to, say, a 10-glass group, which given
that we started with a zero-glass group gives us the 11 groups that I started out
positing that we would need. As the experiment progressed, the number dying in each
group as well as the cause of death, and the health of those still alive, would be