In its simplest expression, the purpose of program evaluation is to explore the logic that links a set of related activities to their expected results. Hence, program evaluation serves to determine the extent to which the logic of a program has unfolded as expected. A prerequisite to this assessment is to have a program (evaluand) that is adequately defined. This article explores the potential impacts of having an ill-defined or incomplete definition of a program that is about to be evaluated. It discusses some strategies that evaluators can explore to avoid what may well turn out to be a fatal flaw in what is already a rather challenging research process.