Epistemic Uncertainty
Epistemic uncertainty is a type of uncertainty that arises from a lack of knowledge or information about an object, process, or system.
It is called “Type II uncertainty” or “reducible uncertainty” because it can be decreased or eliminated through additional data, experiments, observations, model refinement, and expert judgment. It is knowledge about not knowing, in contrast to aleatory (random) uncertainty, which is inherent in the very nature of the phenomenon.