Abstract
The Japanese Health Care system basically does not allow the insured to enjoy uninsured medical service. If they do receive it for some sickness or injury, they usually cannot receive any insurance money for the matter even when they are also given insured medical service for it. Thus the system prohibits not only uninsured medical service but also a mixture of insured and uninsured medical services. The aim of the paper is to assess the institutional effects of the mixed treatment prohibition of the Japanese Health Care system from an economic point of view. We formulate a simple theoretical model and study the differences of mixed treatment prohibition and permitted mixed treatment. For the latter, we have the case in mind that if the insured are given both insured and uninsured medical service, they receive insurance money only for insured medical service. Through the comparative institutional analysis, we obtained two main results: (1) the higher the average income level of the insured or the cheaper the medical service, the more socially desirable the permission of mixed treatment, and (2) there is the case that the mixed treatment permission rather reinforces medical equality: the difference between the levels of medical service chosen by the insured with the lowest income and by those of the highest income, decreases when the insured of the lowest income choose the highest level of insured medical service under the mixed treatment prohibition. It has been taken for granted that the mixed treatment prohibition together with the public compulsory insurance system contribute to medical equality in Japan. The second result suggests that we should accept the idea with some reservations.
