Classical Trade Theory 梁俊伟山东大学（威海） 商学院 Key Hypothesis of Classical School Labor is the single production factor Value is only created by Labor Trade is made because of the differentiation of productivity, say, the technology. Theorists Adam Smith 有力地抨击了重商主义的主张，力主自由经济，奠定了自由贸易的理论基础。 提出了绝对优势理论，从供给角度为国际贸易理论的发展指明了方向。 Absolute Cost              Absolute Advantage             Trade Defects: neglecting the trade btwn some economies that one of them take absolute advantage in all products. David Ricardo Relative Cost              Relative Advantage             Trade Ricardo Model Hypothesis One factor_labor Homogenous in different industry in one nation Freely mobile intranationally, not internationally Constant returns to scale Complete competition in both product and factor market No transportation cost and other transaction costs 2X2X1 model Linear Production function (proof required) AA-----Model Qi=fi(L) (i=x,y) X=axLx X=bxLx   Lx+Ly=LA Y=ayLy Y=byLy RA-----Model What’s good if trade? 直线型的PPF意味着机会成本固定不变； 斜率分别为-ay/ax和-by/bx; 封闭条件下的相对价格分别为:        Pa=PXa/PYa= ay/ax;         Pb= PXb/PYb= by/bx  International Eq Price International Eq Price Trade Benefits: Aggregate Welfare CIC of both A and B rise to a higher level Resource Distribution Set A as an example       Change from Y to X will save 1/aY labor and meanwhile increase X output by (1/aY ) aX. After trade at the world price, A can gain the total Y by (aX/aY)PW(why?)       (aX/aY)PW  (aX/aY)Pa=1 Real Wages Closed Economy Complete competition makes the wage equal. normal wage: wa=pXa.aX=pya.ay Real wage: wa/pXa=aX       wa/pYa=ay  Open Economy normal wage: wa=pXw.aX Real wage: wa/pXw=aX                                                     wa/pYw=pXw.aX/pYw=pwax ay (deduction required) Empirical Research Empirical Research Empirical Research Empirical Research GDA Mac Dougall,1951, “British and American Export: A Study Suggested by the Theory of Comparative Costs”, Economic Journal, Vol.61, pp.697-724. * School of Business Shandong University (Weihai) * School of Business Shandong University (WeiHai) ax bx   ay bx/by, by/bx ay/ax X Y B B’ A’ A Eb Ea Closed Economy A’ A P1 P2 C2 C1 Ea PW=PXw/PYw Pw=P1 Pa Pw=P2 Pa  Xa Ya Xa 0 aXLA-Xa P=PX/PY Pa XC-XP Xa 0 aXLA-Xa P=PX/PY Pa Surplus Supply Curve of A in X Surplus Demand Curve of B in X Pb Pw XC-XP A A’ Ca Ea PW D X X Y B B’ Cb Eb PW F Y Trade Triangle 

Intl Trade 2 古典贸易理论.ppt