Evaluation research in environmental sociology and in environmental psychology : methodological aspects

From a methodological point of view, the authors address social science research dealing with the evaluation of programs in the area of environmental protection. The relevant concepts are defined, and issues of research design and data gathering are discussed. Specifically, experimental and quasi-experimental designs are compared. The authors further discuss problems such as selection effects, treatment contamination, representativeness, reactivity of measurement, influences of social desirability on responses, and the pros and cons of individual versus aggregated data. In an outlook on possible future developments, the aspects of methodology and of institutionalizing evaluation research are addressed.