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...

We test whether financial incentives have an effect on weight reduction in a randomized controlled trial involving 700 obese persons assigned to three experimental groups. While two treatment groups obtain €150 and €300, respectively, for achieving an individually assigned target weight...

This paper investigates the method of matching regarding two crucial implementation choices, the distance measure and the type of algorithm. We implement optimal full matching a fully efficient algorithm and present a framework for statistical inference. The implementation uses data from the...

This paper examines the effect of copayments on doctor visits using the German health care reform of 2004 as a natural experiment. In January 2004, copayments of 10 euros for the first doctor visit in each quarter have been introduced for all adults in the statutory health insurance. Individuals...

Arguably, one of the most important developments in the field of applied economics during the last decades has been the emergence of systematic policy evaluation, with its distinct focus on the establishment of causality. By contrast to the natural sciences, the objects of our scientific...

Using a retrospective monthly calendarium of individuals' major economic activities, this paper characterizes the monthly employment and unemployment rates and the monthly transition intensities between the states of employment, unemployment, and out-of-thelabor- force for the German labor...

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...

It is often argued that the labor market outcomes of several "problem groups" of German workers suffer disproportionately in an economic downturn. These groups are women, the unskilled, and young and old workers, respectively. Using monthly individual-level data for West Germany for the period...

Trotz des beachtlichen personellen und finanziellen Aufwands, der in der Bundesrepublik für die Durchführung arbeitsmarktpolitischer Maßnahmen betrieben wird, ist ihr Erfolg in keiner Weise gesichert. Im Gegenteil, die bisherige Evaluierungspraxis verletzt nahezu durchgängig eine der...