Uncertainty assessment is hard because it requires us to assess what we do not know. How do we quantify what we don't know? Why even bother with assessing uncertainty? We bother because assessing uncertainty can help us to make better decisions. Domain experts best understand the assumptions and approximations of their models and interpretations, but along with great expertise comes great responsibility. It is the experts' responsibility to assess and convey the uncertainties of their interpretations to the decision makers. Moreover, understanding the uncertainties associated with different data is critical for integrating different sources of information, for quantifying the value of different information, and for making decisions about acquiring new information.