A common understanding of the enterprise is critical for any improvement effort. Modeling is an approach to providing a common understanding of the enterprise and how to achieve its desired future condition. The Enterprise Engineer must determine how to design and improve all the elements in an enterprise to enable the enterprise to achieve its goals. This paper presents a methodology for the classification of living models of the enterprise. It presents the results of a field study using a survey method approach on the use of enterprise models and a manufacturing enterprise reference model. The methodology will enable the common understanding and reuse of enterprise models.