Measuring the external effects of public programs

This paper reports attempts to measure systematically the external effects of public programs. Specifically the paper focuses upon those intangible (that is, nonquantitative) externalities, which are such a potent force in generating community opposition. The general concept of external effects is reviewed, in order to clarify the requirements of any systematic analysis. Two approaches, one using multidimensional scaling, the other using the semantic differential technique, are described and demonstrated in a simple empirical example. These techniques should facilitate the development of cross-sectional and aggregate analyses of conflict situations.