Disciplinary Boundaries and Evaluation Methodology.
It is ironic that in a field with such a rich array of alternative evaluation approaches, there still ex- ists, among some evaluators, a tendency to fall prey to the law of the instrument
120 Part II • Alternative Approaches to Program Evaluation
fallacy2 rather than to adapt or develop evaluation methods to meet the needs of the program, the stakeholders, and the identified evaluation questions. In many cases, the law of the instrument fallacy in evaluation is grounded in the methods of the discipline of the evaluator’s original training. However, Scriven (1991c) has effectively argued that evaluation is not a single discipline but a transdiscipline that, like logic, design, and statistics, is applied to a wide range of disciplines.
Thus, our presentation of approaches is not meant to encourage a single ap- proach, but to encourage the reader to adopt the approach or elements of different approaches that are appropriate for the particular evaluation he or she is planning.