D·13
Decisions & Judgment
Look for the Missing Data
Your evidence is made almost entirely of things that survived long enough to be visible.
- Evidence
- proven
- Topic
- Decisions
- Things to do
- 3
- Read
- 1 min
provenHow strong is the evidence?
Tested again and again, by different people, and it keeps coming out the same. You can lean on this.
- Abraham Wald, Statistical Research Group, 1943
- the returning-bombers analysis
Why it works
Wald's planes came back with holes in the wings; the armour belonged where the returning planes had no holes, because those planes did not return.
What to do about it
- For every success story, ask who did the same things and failed. If you cannot find them, you cannot use the story.
- Before copying a strategy, find the base rate of people who tried it.
- In your own review: count the deals you never heard about, not just the ones that closed.
Where people go wrong
Founder biographies, bestseller lists, and any advice derived from studying only winners.
Read next
- Sunk Costs Are Not CostsMoney and years already spent are gone whatever you now decide. The only question is forward value.proven
- Start From the Base RateAsk what usually happens to cases like this one before you consider what is special about this one.proven
- The Planning FallacyYour estimate of how long this will take is an estimate of the best case, and you know it is not the best case.proven
- The Pre-MortemBefore committing, assume it is eighteen months later and the project has failed. Write the story of why.solid