社會困境？－－全民健保總額預算制下醫療提供者策略的均衡分析

Social Dilemma？ —An Equilibrium Analysis of Providers’ Strategies under Global Budget

本文建立總額預算支出上限制下，醫療服務提供者行為策略的理論模型。利用比較靜態分析，探討醫療成本、支付標準、醫療機構之獲利指標、醫療機構數及總額預算額度對各醫療機構均衡服務量和社會整體總服務量的影響和效果。同時，探究政府是否可能透過此制度設計，使醫療機構之均衡服務量達到政策最適服務量。再者，探討醫療機構間是否有同儕合作以獲取較均衡更多利潤的可能性。最後，說明此政策變動對醫療機構的成本衝擊。結果發現：（一）支付標準、獲利指標、總額預算額度對均衡服務量和社會整體總服務量皆有正向的影響；醫療成本對均衡服務量和社會整體總服務量有負向的影響；醫療機構數對均衡服務量有負向影響，但對社會整體總服務量有正向影響。（二）醫療機構數越多，則支出上限制下的均衡服務量將越趨近於政策最適服務量。（三）在缺乏管理階層的協調與監督的情況下，個別醫療機構都有偏離同儕合作的誘因。（四）在論量計酬制下擴充設備規模的醫療機構，在總額預算制實施後之均衡利潤會變小。

The purpose of this paper is to analyze the welfare effects of global budget cap policies. The global budget cap policies have two remarkable features. First, the cap is fixed exogenously by the regulator. Second, there is an inverse relation between unit payment and quantities supplied. The quantity decisions of all providers together determine the relative value unit which is automatically reduced if the providers choose to supply more health services. It is obvious that a global budget creates a conflict between providers’ individual economic self-interest and their collective interest in constraining total billings within the capped budget which shares the features of common-property resources. Conventional wisdom about common-property resources predicted overuse and depletion of such a resource, the so-called “tragedy of the commons”. However, practical evidence of the provider’s utilization responses to the global cap differed notably across the countries. This paper provides a theoretical analysis of the Nash equilibrium service quantities under global budget cap policy. The effects of the medical cost, relative value unit schedule, index of profitability, and amount of global budget to the health care providers and social welfare are examined by comparative analysis. In addition, we also compare the service quantities between the Nash equilibrium and the social optimum under the global budget cap policy. Furthermore, the possibilities for health care providers to collude to gains more profits are discussed. Finally, the impact of the global budget policy on the cost of health care institutions is explored. The results of theoretical research are as follows: First, the relative value unit schedule, index of profitability, and amount of global budget have positive influences while the medical cost has negative effect on the optimum at the Nash equilibrium as well as on total social service quantities. Total social service quantities are negatively while the Nash equilibrium quantities are positively affected by the amount of health care providers. Second, Nash equilibrium service quantities are smaller than the social optimum unless the numbers of the medical care institutions are infinitely large. Third, the individual health care provider has the deviation incentive to defect the collusion. The high service quantity is the provider’s dominant strategy. Finally, the health care providers have invested in fixed equipments under fee-forservice system will face a smaller profit margin when the payment system transferred to the global budget.