The Circle of Competence Let's talk about the "circle of competence", a little summary to try to engrave the concept in my mind. Everyone has a specific area of expertise, within which he or she has a deep knowledge. This is the circle of competence. Problems arise because most of us tend not to have a clear understanding of the limits of this competence and we often confuse what we know and what we think we know. To get a solid grasp of this difference is of the utmost importance if we want to be able to make effective decisions. The rule is: define what you really know and stick to it. In the meantime, though, we can try and expand our circle of competence by learning every day.