台灣汽車車體損失險上的訊息不對稱問題之研究

A Research on the Asymmetric Information Problems in the Automobile Insurance Market of Taiwan

汪琪玲(Chi-Ling Wang)

指導教授 ： 曾郁仁

國立臺灣大學/管理學院/財務金融學研究所/博士(2006年)

https://doi.org/10.6342/NTU.2006.00707

摘要

摘 要
本文第一個子題分析台灣車體損失險市場訊息不對稱問題，區分為險型態、或風險趨避態度之訊息不對稱。除著眼新車、舊車保單有無樣本異質性，並對甲、乙、丙式保單，兩兩交叉比對。條件相關分析結果發現：三種保單間，訊息不對稱問題不盡相同。甲式和丙式或乙式和丙式車體損失險保單之間，存在風險型態的訊息不對稱；甲式和乙式車體損失險保單間，則存在選櫻桃現象。不控制新車效果所得出的推論，大致是堅實的，只是新車的訊息不對稱力量較強，差異體現在理賠金額門檻值效果上。整體樣本中，可看到保險公司隨金額加強控制理賠或核保、舊車子樣本中，則看到投保者風險趨避程度隨金額增強。研究對象的區域，亦不會大幅改變推論方向，只有程度差異而已。第二個子題，分析台灣車體損失險市場的動機效果，Li, Liu and Yeh (2005)利用台灣車體險市場跨年契約轉換資料，成功離析掉逆選擇，檢測出自負額會引發道德風險下的動機效果。依循該文獻，本文改從保障項目檢測市場的動機效果。在甲式轉丙式及乙式轉丙式保單，本文都得到動機效果的證據，隱含高保障契約，易讓投保人疏於小心。但在甲式轉乙式保單，本文無法確切斷定有動機效果，因為，若切除甲式的不明原因出險，無法得到正面的證據；若不切除，雖得到肯定結論，卻無法認定真為動機效果、還是擴大理賠範圍所致。透過理賠門檻值變化，本文發現保險公司在高額理賠時，有較強的稽核動機。同時，本文發現，契約自負額設計差異的干擾，並沒有扭曲論文中的檢定推論。

關鍵字

訊息不對稱 ； 道德風險 ； 逆選擇 ； 動機效果 ； 汽車保險

並列摘要

Abstract
The first part of this research on the asymmetric information problem in the automobile comprehensive insurance of Taiwan emphasizes on separating it into asymmetric information about risk type and asymmetric information about the risk aversion attitude. We compare the heterogeneity between new car and old car policies; and analyze pair-wisely on the policies of type A, B and C. By conditional correlation analysis, we find evidences to support the existence of asymmetric information about risk type between type A and C as well as type B and C. Our empirical evidences indicate that there could exist asymmetric information about the risk aversion attitude between type A and B. Our results are robust to the car age. The only difference is the threshold effect about the claim amount which comes from that new cars get stronger asymmetric information. In the full sample, the audit from insurance company is more severe when the claim amount increases. On the other hand, in the sub-sample (car age is more then three years), the insured becomes more risk averse when the loss amount increases. Our conclusion also won’t change by the choice of tested data area. The only difference is in the strength of their asymmetric information. Second part of this research using the data of switching contracts through years in comprehensive automobile insurance of Taiwan, Li, Liu and Yeh (2005) successfully isolate the adverse selection problem and find deductible in insurance contract provide incentives on moral hazard. This paper follows their methodology to test the same problem in the same market from the view point of insurance contracts with different coverage items. This paper finds that incentive effect exists when policyholders switch their policies from contracts type A or B into contract type C. It implies that high coverage contracts may cause careless driving. But this paper can not confirm the incentive effect when the policyholders switch their policies from contract type A into contract type B. When the unknown reason claims are cut out, there is no evidence of incentive effect, but when the unknown reason claims are included, the evidence existed. But we can not make sure that is the truly evidence of incentive effect, or that is only from more coverage items including more claims. We also found the evidence to support that insurance companies tighten auditing criteria when the claim amount rises. All outcomes in the paper are generally held despite different deductible

並列關鍵字

asymmetric information ； moral hazard ； adverse selection ； automobile insurance

參考文獻

曾郁仁、蔡英哲、鄭安峰，2006，「台灣車體損失保險不對稱訊息的實證研究」，管理學報，23卷2期：頁227-240。

Abreu, D., Pearce, D., & Stacchetti, E. 1990. Toward a theory of discounted repeated games with imperfect monitoring. Econometrica.58(5): 1041-1064.

Arnott, R., & Stiglitz, J.E. 1988. Randomization with asymmetric information. Rand Journal of Economics. 19(3): 344-362.

Cardon, J.H., & Hendel, I. 2001. Asymmetric information in health insurance: Evidence from the national medical expenditure survey. Rand Journal of Economics.32(3): 408-427.

Cawley, J., & Philipson, T.J. 1999. An empirical examination of information barriers to trade in insurance. American Economic Review. 89(4): 827-846.