Death certain, hour uncertain

uhrFollowing last week’s blog in which I talked about risk, I want to talk today about a closely related subject: uncertainty. The only certain thing in life is that it’s deadly. The rest, up to the exact timing of death, is uncertain. This makes life thrilling, but also somewhat uncomfortable.

As we all know, uncertainty is inherent to the scientific enterprise – actually, it’s the raison d’être of science. By exploring the unknown we want to reduce the uncertainty about the world around us. But scientific results will always come with uncertainty, not least because we are humans. Even the most accurate science has always an error margin, which may depend on the precision of the instrument used and, of course, our own interpretation of the result.

In other words, scientists embrace uncertainty and they see it as their mission to reduce it as much as possible by generating new knowledge. Politicians are different. They don’t like uncertainty, many of them even hate it. The reason why many politicians ask scientists for their advice is precisely because they want to get answers that are certain, in order to underpin political decisions. So they don’t want an answer like “the result could be a or b”, but expect scientists to give them a helping hand and provide clear guidance. This is a difficult task, not least because many political decisions are about the future, which by nature is uncertain.

How to communicate uncertainty to politicians is one of the big enigmas of the science-policy relationship. Here I would like to give a few recommendations. First, we need to communicate that such a thing like uncertainty exists and that even the best advice will not provide 100% certainty. The advice provided by scientists can make the lives of politicians easier, e.g. by reducing uncertainty as far as possible, but the final decision will always be with the politician and there is a certain likelihood that he or she will get it wrong, even if following the advice.

Possible paths of Hurricane Sandy (2012)
Possible paths of Hurricane Sandy (2012)

Second, we should not be afraid of communicating uncertainty. Actually, there are many areas in which citizens are already used to deal with uncertainty information, for instance the rainfall probability of tomorrow’s weather forecast. Also when it comes to natural hazards – the potential path(s) of a hurricane, the 1 in a 100 years flood or earthquake – uncertainty statements can often be found in the media. So the scientific concept as such is familiar to most people.

Still, although scientists love to quantify uncertainty, politicians are not interested in whether the uncertainty is 8.2 or 11.7. They want to know in plain language how sure we are (“I am taking a shot in the dark here” versus “I am highly confident that this is going to happen”). This type of language can be found, for instance, in the IPCC reports which are a perfect example of how to communicate uncertainty. The answer to the “How sure are you?” question will help politicians to get an idea of how far they can rely on the evidence and whether they can be attacked on it (also from scientific circles who do not believe in the mainstream scientific opinion!). High certainty strengthens the weight of the evidence, whereas low certainty weakens the case for science to be considered.

Even more important, politicians want to know what the uncertainty means. Does it mean that in the worst case it may cost me a million bucks more or does it mean the potential end of life on this planet as we know it? This information is important, for instance, when assessing risks and discussing the possible application of precautionary measures. This is a point where politicians expect guidance from the scientific community. So don’t focus so much on the numbers, but on the story behind the numbers.

ozone hole
The ozone hole: Strong scientific consensus has provoked political action

Uncertainty also has its positive side. In particular, it gives politicians a room of maneuver as in most cases the uncertainty will allow for the development of various policy options without ignoring the science. Which option to choose is then of course up to the political bargaining. Where it becomes problematic is when politicians choose to go for a policy which goes against a highly certain evidence. Science skeptics – such as climate skeptics – often use uncertainty to underpin their cause or to discredit science (“you are not sure, so why take action”, “this is still within the natural variability” etc.). The best way to tackle this is to talk more about scientific consensus. In fact, there is a great deal of consensus out there on many issues. However, scientists often forget to communicate consensus because it’s incredibly boring for them. Scientists rather like to discuss where they disagree, around the edges of the consensus. This necessary scientific debate is then used by some politicians as an excuse to disregard science. But there are plenty of examples where a strong, united voice by science communicating consensus has actually led to political action – the ozone hole is perhaps the most prominent case.

As many people know, I am a Trekkie, and in the movie Star Trek IV (1986) there is a wonderful dialogue between a decision-maker (James T. Kirk), a scientist (Mr Spock) and a doctor (Bones McCoy):

Spock: Mr. Scott cannot give me exact figures, Admiral. So I will….. make a guess.

Kirk:       A guess? From you, Spock? That’s extraordinary!

Spock to Bones: I don’t think he understands.

Bones: No, Spock. It means he feels safer about your guesses than about most other people’s facts.

Spock: Then I will try to make the best guess I can.

I think this is the best we can do as scientists: in the presence of uncertainty to deliver the best, honest, educated guess we can, based on our knowledge and expertise. This does not mean that our guess will always be correct. After all, also scientists are humans (not all of them are vulcans…). But the chances of getting it right are always higher when following an educated guess rather than a gut feeling.


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