#5: Think and Communicate in Estimates
Probability phrases like “serious possibility” might seem informative, but they are useless.
One of the skills of decision-making is assigning probability estimates to outcomes.
I started doing this after reading in 2016 the incredible book "Superforecasting" by Phil E. Tetlock and Dan Gardner.
The many words and phrases we use around probabilities, such as doubtful, slim chance, rarely, or very likely, are interpreted differently by people. Drastically differently.
Sherman Kent, a legend in intelligence circles, figured this out when a team had agreed to use "serious possibility" when estimating if the Soviet Union would invade Yugoslavia in 1951. It turned out that one analyst thought this meant the odds were 80 to 20, while another thought the odds were 20 to 80—complete opposite interpretations.
"Serious possibility" wasn’t clear.
“A phrase that looked informative was so vague as to be almost useless. Or perhaps it was worse than useless, as it had created dangerous misunderstandings.” Page 55
Here is an example from a New York Times article (capitalization mine).
The origin of the Covid virus remains the pandemic's biggest mystery. Did the virus jump to human beings from animals being sold at a food market in Wuhan, China? Or did the virus leak from a laboratory in Wuhan?
U.S. officials remain divided. The F.B.I. and the Department of Energy each concluded that a lab leak was the MORE LIKELY cause. The National Intelligence Council and some other agencies believe that animal-to-human transmission is MORE LIKELY. The C.I.A. has not taken a position.
The question remains important partly because it can inform the strategies to reduce the chances of another horrific pandemic.
The agencies, hopefully, have specific estimates. However, how journalists communicate this can be interpreted very differently by the public. What does “more likely” mean? Is it 51 percent, 20 percent, or 90 percent? It can mean all those things to different people.
The takeaway is to get yourself in the habit of thinking and communicating to others in numbers—using estimates to escape the vagueness of words.
References
New York Times Editorial Board. (2024, June 3). Opinion: The Covid lab leak theory. The New York Times. https://www.nytimes.com/interactive/2024/06/03/opinion/covid-lab-leak.html
Tetlock, P. E., & Gardner, D. (2015). Superforecasting: The art and science of prediction. Broadway Books.