Retrospective Rating Method and Loss Control Incentive for Insurance

Abstract

追溯費率法(retrospective rating)乃是一種直接反應被保人當期損失經驗之定價方式，在此方式下發生損失較少之被保人將可繳交較少之保費。它是一種結合危險自留基金與保險二者之優點的費率方法，並且具有刺激損失控制之效果。目前在保險實務上雖已受到重視並應用於某些責任險保單，然而保險學術研究尚未證實它是否為一最佳費率模式，本文之目的即在於探討此一問題。本文之研究方法乃是採用代理理倫(principal-agentframework)分析保險人對被保人之保費誘因與提高損失控制之效果二者間之關聯性，以確定追溯費率是否為最適定價模式。根據本文研究發現：(1)若損失控制之努力可以辨識，則追溯費率並非最適定價方式；(2)反之，若因保險人與被保人間資訊不對稱而造成損失控制之努力無法辨識，則追溯費率乃是最適定價方式。

Retrospective rating is a loss-sensitive rating plan, which allows an insured with favorable loss experience to pay less for insurance. It combines the cash flow advantages of self-funding with the advantages of an insured program. Although retrospective rating has been widely applied in practice, the fundamental question whether it can be an optimal rating mechanism is not yet addressed in insurance literature. The purpose of this paper is to examine this question by using the principal-agent framework. The findings of this paper suggest: (1) at the absence of moral hazard problems, the retrospective rating cannot be the first-best optimal scheme, and (2) the retrospective rating is the second-best optimal mechanism when there are moral hazard problems.