Field evidence suggests that people belonging to the same group often behave similarly, i.e., behaviour exhibits social interaction effects. We conduct an experiment that avoids the identification problem present in the field. Our novel design feature is that each subject simultaneously is a...

Since interventions by the public sector generally commit substantial societal resources, the evaluation of effects and costs of policy interventions is imperative. This paper outlines why program evaluation should follow well-respected scientific standards and why it should be performed by...

The context of community-based interventions presents formidable problems for any evaluation analysis. Group-randomized studies do possess ideal properties in theory, but in practice, grouprandomization might not be a feasible alternative at all or group-randomized studies might be contaminated....

Large-scale environmental programs generally commit substantial societal resources, making the evaluation of their actual effects on the relevant outcomes imperative. As the example of the subsidization of energy-saving appliances illustrates, much of the applied environmental economics...