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George Bernard Shaw on Vaccine
Voice From The Past
Compliments of: bmlets@mail.peg.apc.org
On many occasions parents often inquire as to what statistics are available on this
subject. So I thought you may find George Bernard Shaw’s view on the subject of
statistics, taken from the preface of one of his plays entitled ‘The Doctor’s
Dilemmas’, rather interesting.
Public ignorance of the laws of evidence and of statistics can hardly be exaggerated.
There may be a doctor here and there who in dealing with the statistics of disease has
taken at least the first step towards sanity by grasping the fact that as an attack of
even the commonest disease is an exceptional event, apparently overwhelming statistical
evidence in favour of any prophylactic can be produced by persuading the public that
everybody caught the disease formerly. Thus if a diseases is one which normally attacks
fifteen per cent of the population, and if the effect of a prophylactic is actually to
increase the proportion to twenty percent, the publication of this figure of twenty per
cent will convince the public that the prophylactic has reduced the percentage by eighty
per cent instead of increasing it by five, because the public, left to itself and to the
old gentlemen who are always ready to remember, on every possible subject, that things
used to be much worse than they are now, will assume that the former percentage was about
100.
The vogue of the Pasteur treatment of hydrophobia, for instance, was due to the
assumption by the public that every person bitten by a rabid dog necessarily got
hydrophobia. I myself heard hydrophobia discussed in my youth by doctors in Dublin before
a Pasteur Institute existed, the subject having been brought forward there by the
skepticism of an eminent surgeon as to whether hydrophobia is really a specific disease or
only ordinary tetanus induced (as Tetanus was then supposed to be induced) by a lacerated
wound. There were no statistics available as to the proportion of dog bites that ended in
hydrophobia; but nobody ever guessed that the cases could be more than two or three per
cent of the bites. On me, therefore, the results published by the Pasteur Institute
produced no such effect as they did on the ordinary man who thinks that the bite of a mad
dog means certain hydrophobia. It seemed to me that the proportion of deaths among the
cases treated at the Institute was rather higher, if anything, than might have been
expected had there been no Institute in existence. But to the public every Pasteur patient
who did not die was miraculously saved from an agonizing death by the beneficent white
magic of that most trusty of all wizards, the man of science.
Even trained statisticians often fail to appreciate the extent to which statistics are
vitiated by the unrecorded assumptions of their interpreters. Their attention is too much
occupied with the cruder tricks of those who make a corrupt use of statistics for
advertising purposes. There is, for example, the percentage dodge. In some hamlet, barely
large enough to have a name, two people are attacked during a smallpox epidemic. One dies:
the other recovers. One has vaccination marks: the other has none. Immediately either the
vaccinists or the anti- vaccinists publish the triumphant news that at such and such a
place not a single vaccinated person died of smallpox whilst 100 per cent of the
unvaccinated perished miserably; or, as the case may be, that 100 per cent of the
unvaccinated recovered whilst the vaccinated succumbed to the last man.
Or, to take another common instance, comparisons which are really comparisons between
two social classes with different standards of nutrition and education are palmed off as
comparisons between the results of a certain medical treatment and its neglect. Thus it is
easy to prove that the wearing of tall hats and the carrying of umbrellas enlarges the
chest, prolongs life, and confers comparative immunity from disease; for statistics show
that the classes which use these articles are bigger, healthier, and live longer than the
class which never dreams of possessing such things. It does not take much perspicacity to
see what really makes this difference is not the tall hat and umbrella, but the wealth and
nourishment of which they are evidence, and that a gold watch or membership of a club in
the Pall Mall might be proved in the same way to have the like sovereign virtues. A
university degree, a daily bath, the owning of thirty pairs of trousers, a knowledge of
Wagner’s music, a pew in a church, anything, in short, that implies more means and
better nurture than the mass of laborers enjoy, can be statistically palmed off as a magic
spell conferring all sorts of privileges.
In the case of a prophylactic enforced by law, this illusion is intensified
grotesquely, because only vagrants can evade it. Now vagrants have little power of
resisting any disease: their death rate and their case-mortality rate is always high
relative to that of respectable folk. Nothing is easier, therefore, than to prove that
compliance with any public regulation produces the most gratifying results. It would be
equally easy even if the regulation actually raised the death-rate, provided it did not
raise it sufficiently to make the average householder, who cannot evade regulations, die
as early as the average vagrant who can.
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