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...

This paper provides a preliminary assessment of recent reforms of German employment promotion policy. While several recent studies analyze the impact of measures of employment promotion for the case of Germany, no comparable study exists on the aggregate level, thus precluding any assessment of...

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....

The evaluation of interventions such as active labor market policies or medical programs by means of a randomized controlled trial is often considered the gold standard. However, randomized experiments might face severe shortcomings especially if performed at the group level. One such problem is...

Propensity score matching is a prominent strategy to reduce imbalance in observational studies. However, if imbalance is considerable and the control reservoir is small, either one has to match one control to several treated units or, alternatively, discard many treated persons. The first...

Any serious empirical study of factor substitutability has to allow the data to display complementarity as well as substitutability. The standard approach reflecting this idea is a translog specification – this is also the approach used by numerous studies analyzing the relative capital-skill...

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...

This paper concerns optimal redistributive income taxation and provision of a public input good in a two-type model with a minimum wage policy implemented for the low-ability type, where firms may outsource part of the production process abroad, and where outsourcing is substitutable for...

This paper concerns public input provision as an instrument for redistribution under international outsourcing by using a model-economy comprising two countries, North and South, where firms in the North may outsource part of their low-skilled labor intensive production to the South. We consider...