THE contretemps in Britain over the mumps, measles and rubella (MMR) vaccine
has opened up a whole crate of cans of worms.
At its root is a row about negative results. It started with reports of a
14-year Finnish study which concluded that “causality between immunisation and a
subsequent untoward event cannot be estimated solely on the basis of a temporal
relation”. Just count the issues this raises.
Arguments over vaccination are about fundamental values. Those who believe
that there is no such thing as society, only individuals, won’t be convinced it
was worth taking a (tiny) risk of harming their individual child just to prevent
a future general epidemic: the evidence for the collective benefit is a
negative—look, no epidemic. Even, that is, if they have any feeling for
what “one in two million” actually means. Even if grief over the appearance of
some cruel condition is not propelling them to insist that “everything happens
for a reason” and that someone must be to blame for their child’s problems.
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Numerate scientists who work unstintingly for the common weal may see clearly
through this fog. But woe betide you if your results are negative. Negative
results won’t get you a professorship, nor vice-presidency of the company. You
may be lead author of the paper which proves conclusively that, say, deodorant
poisoning didn’t cause that epidemic of short-sightedness. But this will not get
you invited onto grand committees, it will not get you invitations to dinner
with beautiful people, and it certainly won’t get you a spot on TV.
The sign of hard work is supposed to be, well, positive results. Negative
results don’t look like output to those bean-counting accountant-managers who
run research funding.
But you don’t have to be an acolyte of Karl Popper to appreciate that there
is no science at all without negative results. He argued most convincingly that
there is no such thing in science as a positive result. We make hypotheses. We
try to falsify them. The more we fail, the more justified we are in believing
the hypothesis. That’s all.
Many of science’s most important theories stem from negative results. Think
of the 1887 failure by Albert Michelson and Edward Morley to measure the change
expected in the speed of light as the Earth moves around the Sun.
In mathematics, failure to prove theorems produced much of the most
interesting work of the past century. Even in the most abstract mathematics,
negative results can have everyday effects. The very security of your bank cash
card and much else rests on failure to come up with a quick way of factorising
large numbers.
Despite all these and numerous other examples, we see a deep cultural bias
against publishing negative results. So the ambition of evidence-based medicine,
for example, is deeply undermined by bias against studies which show that
treatments don’t work.
Can anything be done? Well, we have Nobel prizes for outstanding positive
results. We even have IgNobel prizes for research which “cannot or should not be
repeated”. Looks like it’s time to launch the Lebon prizes for most outstanding
negative results of the year.
And I nominate the researchers at the Helsinki University Central Hospital
and the Finnish National Health Institute, for their work on demonstrating the
lack of harm caused by the MMR vaccine.
