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...

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...

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...

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...

Using the location of baroque opera houses as a natural experiment, Falck et al. (2011) claim to document a positive causal effect of the supply of cultural goods on today's regional distribution of talents. This paper raises serious doubts on the validity of the identification strategy...

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...

The ultimate aim of opinion surveys is the provision of information on the distribution of preferences and perceptions at the individual level. Yet, eliciting this information from the data is typically difficult. This paper uses a structural model to explain the answers on a set of questions...

This paper investigates whether and to what extent demographic change has an impact on human capital accumulation. The effect of the relative cohort size on educational attainment of young adults in Germany is analyzed utilizing data from the German Socio-Economic Panel for West-German...

Compulsory military service typically drafts young men when they are at the height of their learning ability. Thus, it can be expected to depress the demand for higher education since skill atrophy and the delayed entry into the civilian labor market reduce the returns to human-capital...