Key points are not available for this paper at this time.
`a very good book indeed... I have read and re-read many parts of the text... Wit, thoughtfulness, graceful style, and practical advice are well mixed... a welcome contribution to the maturing of evaluation into an interdisciplinary field whose function in describing and understanding social programs is as important as its role in explaining or judging those programs' -- Educational Evaluation and Policy Analysis
Cordray et al. (1981) studied this question.