現代公司與傳統公司之差別，在於現代公司之所有權與經營權分開，現代公司之 模型在文獻上稱為動機因子摸犁(incentive scheme model)。本文討論在此動機因子模型型， 關稅與配額之等價性。本文發現在Cournot競爭下，存在動機因子時，董事會利用動機因子 的機制，促使經理人將產量生產至領導者之水準。在此一機制下，配額制度時的價格必高於 關稅制度下的價格，此一結論與Hwang and Mai(1988)等人之結論不同，他們發現在Cournot 競爭時，關稅下之價格等於配額下之價格，即關稅與配額具等價性。利用此一動機因子模型， 本文進一步討論當猜測變量不為零時，關稅與配額之等價性。

　　　　　The separation of ownership and management structures, known as the incentive scheme in industrial organization literature, plays an important role in modern corporations. This separation also constitutes the major difference between a modern corporation and a traditional firm. This paper endeavors to study the price equivalence of tariffs and quotas in an incentive scheme model. It finds that under cournot competition, the board of trustees in modern corporations often initiate incentive schemes designed to push managers to raise output to the Stackelberg leadership level. Consequently, prices under quotas are necessarily higher than those under tariffs. This result stands in contrast to the findings of Hwang and Mai (1988) in which the price equivalence of tariffs and quotas holds under Cournot competition This paper also goes one step further in examining the equivalence of tariffs and quotas when firms' conjectural variations have some value other than zero.