Cone of Uncertainty in Project Management

Posted on March 25, 2010 by


A common piece of trivia those studying for their PMP® often encounter is “When is risk and uncertainty at its highest, and when is it easiest to make changes?” The answer is “at the beginning of the project.” As we work on a project, we learn more and more. As activities are completed, we no longer have to guess what they may cost and how long they may take—we now know how much they did cost and how much time they took. As time goes by, the various risk events either occur or don’t occur which leaves less and less to the unknown. The Cone of Uncertainty is a term that refers to the greatest amount of uncertainty being present at the beginning of a project, and as the project progress, the uncertainty diminishes.