The German health care reform of 2004 imposes a charge of 10 Euro for the first visit to a doctor in each quarter of the year. At first glance, there is no inhibiting effect of this fee on utilization in the German Socio-Economic Panel. However, this study reveals that the true effect is diluted...

The German health care reform of 2004 imposes a charge of 10 Euro for the first visit to a doctor in each quarter of the year. Exploiting random variation in the interview day of the German Socio-Economic Panel, this study finds a substantial effect of the new fee on the probability of visiting...

Theoretical considerations suggest that nonlinear health care price schedules have heterogeneous effects on health care demand. In this paper, we develop and apply a finite mixture bivariate probit model to analyze whether there are heterogeneous reactions to the introduction of a nonlinear...

Twin births are an important instrumental variable for the endogenous fertility decision. However, in many economic settings, twins are not exogenous as dizygotic twinning is known to be correlated with maternal characteristics and fertility treatments. Following the medical literature, we...

We investigate the behaviour of the Lasso for selecting invalid instruments in linear instrumental variables models for estimating causal effects of exposures on outcomes, as proposed recently by Kang, Zhang, Cai and Small (2016, Journal of the American Statistical Association). Invalid...

Heterogeneous effects are prevalent in many economic settings. As the functional form between outcomes and regressors is generally unknown a priori, a semiparametric negative binomial count data model is proposed which is based on the local likelihood approach and generalized product kernels....