一般在社會科學領域，Pareto效率經常是用來衡量制度經濟效率性的準則。惟其要求不能傷害任何一位行為人的嚴格定義，使其在實務的運用上並不可行，因此，Marshall效率的「極大化總剩餘」定義，成為另一種比較可操作的標準。本文說明了制度的設計，首先必須滿足Marshall效率的要求，再進一步搭配強制補償受損者的措施，則此「聯合制度」將也可滿足嚴格的Pareto效率。另外，利用這兩種效率準則與行為人「主觀效用」的連結，本文嘗試定義一種個體角度的經濟效率，這種個體面的效率準則，可以反映出經濟效率的「相對性」。最後，本文也說明了「自願交換」的機制，可以提升制度實施的經濟效率性，可同時符合Marshall效率與Pareto效率的要求。

In the field of social science, “Pareto efficiency” is a commonly used criterion for evaluating institutional efficiency. However, the strict limitation of Pareto efficiency that no harm should be imposed on anyone, makes it impractical. Therefore, the “Marshall efficiency”, which aims at maximizing the total surplus, becomes a useful alternative. This paper indicates that the design of institutions should first satisfy the Marshall efficiency in advance and further compensate the individuals who suffer in the system. Thus joint institution could satisfy the strict Pareto efficiency too. In addition, this paper makes a connection between economic efficiency and individual’s utility levels. Based on this connection, this paper attempts to define a concept of local efficiency, which could reflect effectively the relativity of economic efficiency. Lastly, this paper illustrates that the “voluntary exchange” can improve institutional efficiency. Voluntary exchange will satisfy not only the Marshall efficiency but also the Pareto efficiency.