This article examines many existing measures of uncertainty of basic belief assignments proposed in the literature related to the theory of belief func­tions. Some measures capture only a particular aspect of the uncertainty, others propose a total measure of uncertainty to characterize the information quality of a source of information. We discuss the effectiveness of these measures with respect to four main important desiderata that we consider essential for the definition of a satisfactory measure of uncertainty, i.e. effective entropy of basic belief assignment.