"Reports that say that something hasn't happened are always interesting to me because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know." Donald Rumsfeld.

This method looks at risks from the perspective of certainty: "Known", "Unknown" and "Unknowable" etc. This helps manage risk within the continuous planning and execution processes. Relative risk, experimentation and deferral strategies are developed in conjunction with Transition State planning over iterations of the ACD Cycle to provide continuous risk assessment.