Making the program theory explicit is an essential first step in Theory Driven Evaluation (TDE). Once explicit, the program logic can be established making necessary links between the program theory, activities, and outcomes. Despite its importance evaluators often encounter situations where the program theory is not explicitly stated. Under such circumstances evaluators require alternatives to generate a program theory with limited time and resources. Using source documentation (e.g., lesson plans, mission statements) to develop program theory is discussed in the evaluation literature as a viable alternative when time and resources do not permit "a priori" program theory development. Unfortunately, the evaluation literature is devoid of methodology illustrating how to translate source documentation into an explicitly stated program theory. The article describes the steps in using source documentation to develop and verify a program theory and illustrates the application of these steps. It concludes with a discussion about the feasibility and limitations of this methodology. (Contains 2 figures.)