延續傳統文獻對於風險分攤問題的討論，大抵皆以數學分析方法為主，且幾乎假設交易雙方面對相同的狀態發生機率。本文利用幾何圖形分析方法，清楚且完整地說明在風險分攤下契約線的位置，這不但彌補了大部份文獻在這方面的缺憾，而且本文的方法只須利用簡單的邊際效用遞減的特性，便可以說明大部份文獻中並未說明的契約線為何在兩交易者確定線之間的特性。相較於傳統分析方法，本文顯然提供了一個更簡單易懂且更為有力的闡述方法。再者，本文的分析方法可以輕易地將討論議題轉換到交易雙方面對不同狀態之發生機率相同以外的情形，而做出契約線可以在兩交易者確定線以外的結論。相較於傳統文獻的討論方式，本文的圖形分析法顯然提供了一個應用性更強的論述方式。
In line with the literature of risking sharing, this paper attempts to prove the shape and the position of contact curve by a graphic method. Relative to the traditional mathematical analysis, we set up an easy but powerful method to provide a more complete picture for the contract curve in uncertainty. This approach can be viewed as an alternative method for economists and students in studying the Pareto efficiency of risking sharing. A particular emphasis is that our analysis can be easily extended to explore some interesting issues which are not uncovered by the existing literature.
