本文利用單一代表性個人，和所得水準不同之異質代表性個人模型，分析補充性健康保險與全民健保制度並存的經濟效果。研究結果發現：在強制性的全民健保之外，允許消費者另行購買和部門所提供的補充性保險，可增加風險保護功能，但會稀釋全民健保制度原先具有的所得重分配功能，降低醫療保健財務籌集的公平性。補充性保險對於全民健保的影響，取決於補充性保險的給付形式：定額給付保險不會扭曲醫療服務的市場相對價格，所以全民健保本身的財務不受影響；實支實付保險則會改變醫療服務的市場相對價格，進而增加全民健保的醫療支出。本文分析結果的一個重要政策意涵，即是補充性保險與全民健保的搭配，會產生風險保護與財務籌集公平無法同時兼顧的政策取捨問題。
This paper analyzes the economic effect of supplemental health insurance under a system of national health insurance. Our analysis indicates that the purchase of supplemental health insurance can reinforce the risk-protection function of national health insurance. However, it may dilute the income redistribution effect and reduce the equity of health-care financing. Overall, the impact of supplemental health insurance depends on its reimbursement form. Indemnity insurance does not distort the relative price of medical services, and hence does not affect the financial burden of national health insurance. By contrast, a service benefit policy increases the medical expenditures because it decreases the relative price of medical service. An important policy implication of our analysis is that the mix of supplemental and national health insurance leads to a tradeoff between the function of risk-protection and the equity of health-care financing.
