Validity

Writing a general statement about validity in evaluation is a hazardous business. The field of evaluation is so diverse and complex and it has such an array of models, approaches, forms, and disciplinary homes that generalizing about evaluation is invariably a potentially foolhardy enterprise. Moreover, this is historically disputed territory. Validity is related to truth. They are members of the same family, so to speak. Truth, however you cut it, is an essentially contested concept with little agreement about what constitutes the right basis for truth-seeking activities. Of course, much has already been said about validity. There are various classic explications of validity from some of evaluation's most notable theorists: Donald Campbell, Thomas Cook, Lee J. Cronbach, Egon Guba, Ernest House, Yvonna Lincoln, Michael Patton, ...