The deep structure of an information system comprises those properties that manifest the meaning of the real-world system that the information system is intended to model. In this paper we describe three models that we have developed of information systems decl}.structure properties. The first, the representational model, proposes a set of constructs that enable the ontological completeness of an information systems grammar to be evaluated. The second, the state-tracking model, proposes four requirements that information systems must satisfy if they are to faithfully track the real-world system they are intended to model. The third, the good-decomposition model, proposes a set of necessary conditions that an information system must meet if it is to be well decomposed. The three models facilitate the evaluation of grammars used to analyze, design, and implement information systems and specific scripts that represent implemented information systems.