Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
From 2004 to 2012, the German social health insurance levied a co‐payment for the first doctor visit in a calendar quarter. We develop a new model for estimating the effect of such a co‐payment on the individual number of visits per quarter. The model combines a one‐time increase in the otherwise constant hazard rate determining the timing of doctor visits with a difference‐in‐differences strategy to identify the reform effect. An extended version of the model accounts for a mismatch between reporting period and calendar quarter. Using data from the German Socio‐Economic Panel, we do not find an effect of the co‐payment on demand for doctor visits. Copyright © 2016 John Wiley & Sons, Ltd.