The availability of a large and diverse collection of stored modules such as data relations and decision models is a desirable feature in a decision support system (DSS). However, it is usually infeasible to design a DSS in which every problem instance can be solved using a single module. Instead, it may be necessary to combine several stored modules into an integrated model that is sufficient to solve the given problem. We show that modules such as data files and decision models in a DSS can be usefully represented by a metagraph, a graph-theoretic construct that captures relationships between pairs of sets of elements. In addition to the visualization benefits that graphical representation offers, we show that many useful questions faced by the designers and users of DSS can be addressed by exploiting analytical properties of metagraphs. In particular, we show that the process of model integration can be significantly facilitated by exploiting certain connectivity properties in metagraphs.