The one sentence summary

It is possible to increase the accuracy of forecasts by acting as superforecasters do.


  • Philip Tetlock ran a twenty year study showing that so-called experts were only slightly better at prediction than random guesswork, or, as he put it, “a dart throwing chimp”.
  • There is however a group of ordinary people that can predict the future with a degree of accuracy 60% greater than average. They are superforecasters. 3,000 of them were recruited in 2008 by a US government backed initiative called IARPA. This is how they do it:
  1. Concentrate on clear questions that can be answered, albeit with hard work.
  2. Break seemingly intractable problems into tractable sub-problems.
  3. Strike the right balance between inside and outside views.
  4. Strike the right balance between under- and overreacting to evidence.
  5. Look for the clashing causal forces at work in each problem.
  6. Strive to distinguish as many degrees of doubt as the problem permits, but no more.
  7. Strike the right balance between under- and overconfidence.
  8. Look for the errors behind your mistakes but beware of rear-view mirror hindsight biases.
  9. Bring out the best in others and let others bring out the best in you.
  10. Master the error-balancing cycle: try, fail, analyse, adjust, try again.
  11. Don’t treat commandments as commandments.


  • The dragonfly eye is made up of thousands of tiny lenses, each with a slightly different perspective, allowing it to see in almost every direction simultaneously. An aggregation of views is what makes accurate forecasts.
  • Good forecasters have no illusion of control or prediction. It is important to appreciate the limits of prediction, without necessarily being pessimistic about their value.
  • The US National Intelligence Agency has a scale for certainty v. the general area of possibility.

100%: certain

93% (give or take about 6%): almost certain

75% (give or take about 12%): probable

50% (give or take about 10%): chances about even

30% (give or take about 10%): probably not

7% (give or take about 5%): almost certainly not

0%: impossible

  • Old joke: statisticians sleep with their feet in an oven and their head in the freezer because the average temperature is comfortable.


  • Not much. It’s longer than it needs to be, but the points are excellent.