Introduction: Prophylactic vaccinations play a significant role in health care. As a relatively cost-effective preventive measure they can help to avert transmissible diseases and thus protect not only the vaccinated individuals themselves but also those who have not been vaccinated. In order to...

The classical Heckman (1976, 1979) selection correction estimator (heckit) is misspecified and inconsistent if an interaction of the outcome variable and an explanatory variable matters for selection. To address this specification problem, a full information maximum likelihood estimator and a...

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...