[The impact of co-payments on patient behavior: evidence from a natural experiment].

As part of the Statutory Health Insurance Modernization Act a co-payment of 10 Euros per quarter for the first contact at a physician's or a dentist's office has been introduced with effect of January 1, 2004. Apart from contributing to the financial consolidation of the Statutory Health Insurance the co-payment aimed at changing the patients' behavior toward more self-responsibility. This article shows that physician contacts declined in the year 2004 compared to 2003. However, the share of those patients who had at least one physician contact in both years remained stable. Two Logit models point out that necessary physician contacts still take place, e. g., in case of disabled persons and persons with poor health. In addition, no discrimination of persons of low social status could be observed. The results are also approved by other studies. Therefore, it seems plausible, that the introduction of this co-payment has contributed to a reduction of unnecessary and redundant physician visits.