Copayments for doctor visits and the probability of visiting a physician - Evidence from a natural experiment

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 a physician. In addition, the identification strategy makes it possible to disentangle this effect from the influence of the contemporaneous increase of copayments for prescription drugs. This study provides an example where random variation in the interview day can be used to identify causal effects.