Overprecision Bias
Overprecision is excessive confidence in the accuracy of what you know or predict. An exact estimate or a narrow range can express it when the evidence leaves more uncertainty than the estimate acknowledges.
THE IDEA
Overprecision Bias
Overprecision bias refers to the tendency to be too confident in the precision of one's knowledge or predictions. It can appear in an estimate that claims more accuracy than the evidence supports, or in a range that is too narrow to reflect the uncertainty. This bias is a subset of the broader overconfidence effect.
Example from Star Trek
In the quote below, Spock provides an extremely precise odds calculation (7,824.7 to 1) for escaping, which implies a false sense of accuracy:
KIRK: Mr. Spock, can we get those two guards? What would you say the odds are on our getting out of here? SPOCK: Difficult to be precise, Captain. I should say approximately 7,824.7 to 1.
The many unknown variables give the audience reason to question the claimed precision. A later escape alone would not disprove a low-probability estimate.
Real-World Implications
- In business, managers may present financial forecasts with overly precise numbers, ignoring inherent volatility.
- In medicine, doctors might give survival probabilities with false precision, affecting patient decision-making.
- In everyday life, people often state their confidence in opinions with unwarranted exactness.
Mitigation
Explain the basis of an estimate and the uncertainty around it. A range can help, but only if its width is justified; a narrow interval can convey false confidence too.
When to use it
A project manager provides a timeline with exact dates instead of ranges, risking overpromising.
A financial analyst presents a single stock price target instead of a confidence interval.
A doctor gives a patient a survival rate of '73.5%' without explaining the margin of error.
A voter asserts a candidate will win 'by 3.2%' based on early polls with low sample sizes.
FROM THEORY TO EVERYDAY LIFE
In practice
Spock's Odds
In Star Trek, Spock gives Kirk an extremely precise odds estimate (7,824.7 to 1) for escaping, illustrating false precision in uncertain circumstances.
Business Forecast
A CEO projects 'next quarter revenue will be $10,273,500' instead of giving a range like '$10M-$10.5M', suggesting unwarranted certainty.
A MOMENT TO REFLECT
Put it to work.
When have you given an overly precise estimate and later realized it was misleading?
How can you express uncertainty more honestly when making predictions?
What systems can you put in place to check for overprecision in your own decisions?
Often confused with
CONTINUE THE CONVERSATION
Source texts
- The Scout Mindset (Julia Galef)