[Switching sickness funds and risk compensation mechanisms in the statutory health insurance system in Germany--empirical results from the cooperative health research in the region of Augsburg (KORA)].

Since 1996, all citizens of the Federal Republic of Germany who are insured in the statutory health insurance system are entitled to switch their sickness fund. The rationale of this regulation was to strengthen elements of competition in this system in order to stimulate the sickness funds to improve the efficiency of health care and to respond to consumers' preferences. Simultaneously, to avoid the implicit incentives for sickness funds to engage in risk selection, a risk compensation mechanism was introduced, including as morbidity-related risk adjusters age, sex and incapacity to work. Based on the KORA survey S4 (1999/2001) we take the case of switching behaviour in the region of Augsburg, and analyse whether this risk adjustment scheme was working effectively. The results show that persons changing their sickness fund were characterised by a comparatively smaller burden of chronic diseases and by a less frequent utilization of inpatient health care. Under these conditions, differences in the contribution rates do not accurately reflect differences in the performance and efficiency of sickness funds. Moreover, the migration of good risk to sickness funds with favourable contribution rates threatens the principle of financial solidarity. Therefore, the system of risk equalisation has to be developed towards measuring the risk volume borne by the sickness funds more precisely than hitherto.