The concept of the Circle of Competence has been used over the years by Warren Buffett as a way to focus investors on only operating in areas they knew best. The bones of the concept appear in his 1996 Shareholder Letter :
What an investor needs is the ability to correctly evaluate selected businesses. Note that word “selected”: You don’t have to be an expert on every company, or even many. You only have to be able to evaluate companies within your circle of competence. The size of that circle is not very important; knowing its boundaries, however, is vital.
“I’m no genius. I’m smart in spots—but I stay around those spots.” — Tom Watson Sr., Founder of IBM
In fact, Charlie Munger takes this concept outside of business altogether and into the realm of life in general. The essential question he sought to answer: Where should we devote our limited time in life, to achieve the most success? Charlie’s simple prescription :
You have to figure out what your own aptitudes are. If you play games where other people have the aptitudes and you don’t, you’re going to lose. And that’s as close to certain as any prediction that you can make. You have to figure out where you’ve got an edge. And you’ve got to play within your own circle of competence. If you want to be the best tennis player in the world, you may start out trying and soon find out that it’s hopeless—that other people blow right by you. However, if you want to become the best plumbing contractor in Bemidji, that is probably doable by two-thirds of you. It takes a will. It takes the intelligence. But after a while, you’d gradually know all about the plumbing business in Bemidji and master the art. That is an attainable objective, given enough discipline. And people who could never win a chess tournament or stand in center court in a respectable tennis tournament can rise quite high in life by slowly developing a circle of competence—which results partly from what they were born with and partly from what they slowly develop through work. So, the simple takeaway here is clear. If you want to improve your odds of success in life and business, then define the perimeter of your circle of competence, and operate inside. Over time, work to expand that circle but never fool yourself about where it stands today, and never be afraid to say “I don’t know.”
Reference: Understanding your Circle of Competence: How Warren Buffett Avoids Problems