건강보험에서 피보험자와 의료서비스 공급자 양쪽의 도덕적 해이가 의료서비스 이용에 미치는 영향

This study analyzes the optimal insurance contract in health insurance when moral hazard exists in insureds and medical service providers. Three cases are considered: when moral hazard exists only in insureds, when moral hazard exists only in medical service providers, when moral hazard exists in both sides. We first find that the optimal insurance is full insurance without moral hazard. Second, the optimal insurance is partial insurance in the first case, whereas full insurance is optimal in the second case. The medical service consumption of the former case can be greater or less than that of the latter case depending on the utility function, health recovery and cost function of the providers. Third, the insurer can design the treatment fee system, then the fixed payment system is optimal to reduce moral hazard of the providers. Howerver, the system may decrease the provider’s effort and consequently, the supply of medical service may decrease as well. Lastly, the consumption of medical service for the last case can be greater or less than that of the other cases. In particular, it is difficult to regard the moral hazard as the overtreatment since the effect of moral hazard of both sides can be offset.