Circle of Competence

Know what you know, know what you don’t know, and make high-stakes bets only inside your competence.

What's your IQ?

Take the IQ test

25 questions · about 12 minutes

What would you score? Try question 1.

Which option completes the grid? One tap, no sign-up.

A strategy model. All mental models

How it works

Circle of Competence isn't just theory: it's a practical framework for better decisions. This page explains how it works and how to apply it.

The power of Circle of Competence comes from its ability to compress complexity. A good mental model acts like a lens: it brings the important features into focus.

How to apply it

Define where you have real understanding versus surface familiarity. Delegate or learn before acting outside the circle.

Example

A great software engineer may still make poor investments in biotech without domain expertise.

When to use it

Use Circle of Competence when facing complex decisions with multiple variables. It's especially powerful when conventional wisdom seems wrong or when you're operating in unfamiliar territory.

Common mistakes

Over-applying: Not every problem benefits from this model. Match the tool to the situation.
Under-applying: People learn the model but don't practice it. Application takes repetition.
Misunderstanding the principle: Surface-level understanding leads to poor execution. Study the examples.
Ignoring context: The same model works differently in different domains. Adapt accordingly.

Practice exercises

Identify a current decision you're facing. Write down the assumptions you're making. Challenge each one.
Look at a past failure. Apply Circle of Competence retroactively: would it have changed the outcome?
Teach the model to someone else. If you can't explain it simply, you don't understand it well enough.
Set a reminder to apply this model once per week for the next month. Track the results.