Clarifies the application of cost-effectiveness to education, using the RAND studies of education in Colombia as an illustration. Cost-effectiveness can only be judged in comparison with alternatives. Only when inputs and outputs are completely measurable in dollars can a cost-effectiveness study be self-contained. Differences of 10 percent or less are not significant. Resources must be distinguished from the cost of the resources, especially where the availability of trained personnel is a limiting factor. A single measure of effectiveness cannot meet the needs of all educational decisionmakers, yet single measures are usually offered. Given equal-cost alternatives to consider, the decisionmaker can choose among programs in terms of his own value structure. Equal-effectiveness programs are nearly impossible to construct in education, since so much is unquantifiable. (Delivered at the cost-effectiveness seminar for the National Association of Educational Broadcasters in Washington, November 1970.) 8 pp.