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Dealing with Uncertainty

Dealing with Uncertainty


My name is Andy Hart. I’m a scientist at FERA in
the UK and also work with EFSA. I have a special interest in things
that are well, uncertain, which is what I’m here to
talk to you about today. Virtually all decisions in life
are affected by uncertainty. For example, when we travel by car,
we have to decide when to start, in order to get to our
destination on time. We know there might be delays
due to traffic or other problems, so we are uncertain how
long the journey will take. We might get an estimate of the
journey time from a travel website, but it will rarely be precisely correct. The actual time might be shorter,
if the journey goes well, or longer, if there’s more traffic. It might take much longer if our car
breaks down, but that’s less likely. So there is a range of possible
times the journey might take and some are
more likely than others. That means there is
a risk of arriving late. To reduce the risk, we may decide
to allow more time for the journey, especially if arriving late
would have bad consequences. The more time we allow,
the lower our risk of being late. The same principles apply
to decisions on food safety. Scientists might be asked for
advice on the risk from a chemical, or a new food or disease. We use the best available science
to give the best advice we can but there will be limits
to how much we know. For example, there will be
some uncertainty about the levels of a chemical in the food, about
how much is eaten and consequently, how much of the chemical
people are exposed to. Also, we won’t know precisely
how toxic the chemical is, which affects where we
set the Safe Level for it. So, as for the journey time
with the car, our estimate of the exposure will be uncertain. There is a range of possible values
and some are more likely than others. As a result, there may be a chance
of exposure being above the Safe Level, as well as a chance of being below it. Once again, decisions that are made
will be affected by the uncertainty. If the chance of exceeding a Safe Level
is high enough, then those responsible for making decisions may
consider removing the chemical or replacing it with an alternative. The role of scientists is
to provide scientific advice. The critical point is that our advice
should be more than just a best estimate. People making decisions need
information on the range of things that might happen
and how likely they are. If the uncertainty is just too
great to provide this, then we need to make that clear so it can be
taken into account in decision-making. So, when you see information on
uncertainty, that isn’t a failure of science. On the contrary, we need
information on uncertainty. We can never be certain of the future,
but if we take account of uncertainty we can make better decisions
both in food safety and in everyday life.

Comments (1)

  1. I also like the word probability

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