During the last years a number of approaches to information modeling have been presented. An information model is then assumed to be expressed in some formalism based on a set of basic concepts and construction rules. Some approaches also include inference rules, but few include consistency criteria for information models. Two different approaches to information modeling have been analyzed within the framework of first-order predicate logic. In particular, their consistency criteria are compared with that of predicate logic. The approaches are completely expressible in predicate logic and the consistency criteria have a logical counterpart only when a set of implicit assumptions is stated explicitly.