Circle of Competence

Posted on — | 3 min read
Mental Models, Books
Book: The Great Mental Models Vol.1


It’s where you know what you’re good at and what you’re not good at. Staying around the spots where you are good at stuff, will give you an edge over others. This, to me, loosely translates into 3 things:

  1. Known knowns: you know what you’re good at and you know those things very well. You probably know it better than most people.
  2. Known unknowns: you know what knowledge you’re lacking, you know what your weaknspots are, you kinda know exactly what it is you want to improve on
  3. Unknown unknowns: you don’t know what you don’t know. You don’t even know some of the things that exists which are either in the field you specialize in or related to it.


Imagine an old man (Lifer) in a small town that knows everything that happens in the town - the politics, the scandals, the transactions, the relationships, the affairs, the births, the deaths, everything. Then a new guy (Stranger) comes to town, talks to some important people and gets an idea of what the town is like. Lifer has a strong knowledge about the town and everything in it, the Stranger thinks he knows everything, but only has surface-level knowledge.


  • the better we are at circle of competence, the better we’ll be able to understand and recognize what we don’t know. That way we can be better equipped when we face uncertain situations.

  • 3 steps to build a CoC:

    1. Be willing to learn. Learn from books, podcasts, articles, experiences and others’ mistakes.
    2. Monitor where you have or want to have a CoC. You need to be honest about your failures in order to reflect and learn from them. Maintaining a journal of your own performance helps with this.
    3. Solicit external feedback. Others see you and your skills in a different perspective. They won’t be biased as you are.
  • CoC is not static, it’s not something you achieve once and let it be. It’s constantly evolving and you must continuously learn and be willing to learn and expand your knowledge. Only then you’ll understand how much you don’t know.

    The more you learn and expand your circle of competence, the more you realize how much you don’t know - Unknown

  • How to operate successfully outside your circle of competence?

    1. Learn at least the basics of the realm you’re operating in. Know that you’re a “Stranger” and that there’s more out there than just the basics that you’ve acquired.
    2. Talk to someone whose CoC in the area is strong. Do some research to at least define the questions you’d want to ask and what info you need to make a good decision.
    3. Use a broad understanding of the basic mental models of the world to augment your limited understanding of the field in which you find yourself a Stranger.


  • Question: What is my circle of competence? As an exercise, pick one area and write down all the things I know and all the things I know that I don’t know.