Think and communicate in explicit probabilities
Replace vague language ("probably," "likely") with numerical probabilities.
Key takeaways
- What it is: Replace vague language ("probably," "likely") with numerical probabilities.
- Why it works: Words like "likely" are systematically ambiguous — one person’s "likely" is another’s 55% and another’s 85%. Numerical probabilities force specificity, make predictions scorable, and create a feedback loop. Without numbers, there is no signal for whether you are calibrated. The discipline of naming a number also forces genuine uncertainty accounting — you cannot say "basically certain" when you have to commit to 95%.
- Evidence: Backed by observational / correlational evidence.
- Avoid: Using round numbers (50%, 70%, 90%) as a default rather than genuinely calibrating — "I think 50/50" is often a hedge, not an estimate.
Why it works
Words like "likely" are systematically ambiguous — one person’s "likely" is another’s 55% and another’s 85%. Numerical probabilities force specificity, make predictions scorable, and create a feedback loop. Without numbers, there is no signal for whether you are calibrated. The discipline of naming a number also forces genuine uncertainty accounting — you cannot say "basically certain" when you have to commit to 95%.
How to do it
- 1When making a prediction, state it as a percentage: "I think there’s a 65% chance this ships by Q3."
- 2Record the number alongside the prediction so you can score it when the outcome resolves.
- 3When someone gives you a verbal probability, ask: "What number would you put on that?"
- 4Revisit old predictions with their numbers quarterly to compute your calibration.
What the evidence says
ObservationalTetlock’s forecasting research found that superforecasters habitually used numerical probabilities and were significantly better calibrated than experts who used verbal descriptions. The practice of using fine-grained probabilities (not just 50/70/90) was associated with higher accuracy in the tournament.
Honest caveat: Correlation between probability-use and accuracy in tournament data; calibration training with feedback is needed for the habit to produce real improvement.
- — Tetlock & Gardner (2015), Superforecasting
- — Tetlock (2005), Expert Political Judgment
Common mistake
Using round numbers (50%, 70%, 90%) as a default rather than genuinely calibrating — "I think 50/50" is often a hedge, not an estimate.
IX Coach asks you to put a number on your confidence for every stated goal or forecast, then tracks actual outcomes against those numbers so calibration improves session over session.
Practice this with IX Coach →