Abstract A number of factors are ensuring that the theory and practice of specific purpose language teaching continue to develop and evolve. One of the major factors is economic in origin, bringing with it the need for ESP program designers to answer to financing bodies as to the effectiveness of their programs. Enthusiasm and positive claims may not be enough to ensure the continued support for existing programs and the launching of new ones by budget-troubled administrators. Evidence of success may become the end product required of the design team, as opposed to merely the prepared materials and the verbal assurance that they are superior to what preceded them. The demand for accountability requires that the ESP specialist add evaluation techniques to his repertoire of skills. It is important that the evaluator does not confuse research and evaluation. The former tests inferences based on observation and phrased as hypotheses; the latter, i.e., evaluation, has as its purpose the provision of those in authority with information which can be used in making decisions about improving or modifying the program. A case study demonstrates an approach to determining the effectiveness of a specific ESP-type program and provides a comprehensive framework within which practicable ESP evaluations can be conceived and carried out.