【正文】 justment of domestic economic structure to adapt to the introduction of external resources. It reflects the introduction of external resources in developing countries, for easing the scarcity of domestic resources is important. Twogap model of the basic equation: IS = MX IS is the difference between investment and savings, known as the savings gap MX is the difference between imports and exports, known as the foreign exchange gap adjusted for the purpose of each variable is to balance the equation.A. Hirschman, Strategy of Economic Development (1958). Unbalanced growthContrary to the theory of balanced growth, in Hirschman39。s opinion, the real bottleneck is not the shortage of capital, but lack of entrepreneurial abilities. Potential entrepreneurs are hindered in their decisionmaking by institutional factors: either group considerations play a great role and hinder the potential entrepreneur, or entrepreneurs aim at personal gains at the cost of others and are thus equally detrimental to development. In view of the lack of enterpreneurial abilities there is a need for a mechanism of incentive and pressure which will automatically result in the required decisions. According to Hirschman, not a balanced growth should be aimed at, but rather existing imbalances— whose symptoms are profit and losses—must be maintained. Investments should not be spread evenly but concentrated in such projects in which they cause additional investments because of their backward and forward linkages without being too demanding on entrepreneurial abilities. Manufacturing industries and import substitutions are relevant examples. These first investments initiate further investments which are made by less qualified entrepreneurs. Thus, the strategy overes the bottleneck of entrepreneurial ability. The theory gives no hints as to how the attitude of entrepreneurs and their institutional influence will be changed in time.P. RosensteinRoden, ‘Problems of Industrialization of Eastern and Southeastern Europe,” Economic Journal (JuneSeptember, 1943). H. Leibenstein, Economic backwardness and economic growth (1957). R. Nelson, “ A theory of the lowlevel equilibrium trap in underdeveloped economies,” AER (Dec. 1956). W. Rostow, The stages of economic growth (1960). R. Nurkse, Problems of capital formation in underdeveloped countries (1953). Structuralist analysis: rigidities, lags, shortage and surpluses, low elasticities of supply and demand. G. Myrdal. Economic theory and underdeveloped regions(1957). R. Prebisch, “The economic development of Latin America and Its principal problems”, Economic Bulletin for Latin America 7 (1950). H. Singer, “ Gains and losses from trade and investment in underdeveloped countries,” AER (may 1950). (3) 在20世紀(jì)60年代后期至70年代初期，發(fā)展經(jīng)濟(jì)學(xué)更加注重貧困和收入分配。增長(zhǎng)的不平衡性，注重農(nóng)村發(fā)展；人力資本的形成，對(duì)人力資源的研究；適用技術(shù)，而是最新技術(shù)的引進(jìn)。Furthermore, in the 1960s the initial concentration on physical capital accumulation was giving way to the concept of investment in humancapital and its implications for development. It was increasinglyrecognized that development depended on productive human agentswho, through their acquisition of knowledge, better health and nutrition,and increase in skills, could raise total factor productivity.（4）70年代至80年代，新古典經(jīng)濟(jì)學(xué)的重新崛起：對(duì)政策導(dǎo)致的市場(chǎng)扭曲的批評(píng)，對(duì)非市場(chǎng)失靈的批評(píng)，對(duì)政府控制的批評(píng)，from “get prices right” to “get policies right”, 市場(chǎng)、價(jià)格、激勵(lì)成為主題。內(nèi)向型發(fā)展戰(zhàn)略轉(zhuǎn)向外向型（出口導(dǎo)向性）戰(zhàn)略，價(jià)格穩(wěn)定和控制通貨膨脹成為首選目標(biāo)，大力推進(jìn)國(guó)有企業(yè)的私有化。注意到發(fā)展中國(guó)家之間的差異性，總體增長(zhǎng)模型被國(guó)別的微觀化模型所取代，國(guó)別的研究和經(jīng)驗(yàn)研究受到越來(lái)越多的重視，新古典經(jīng)濟(jì)學(xué)的基本原理被應(yīng)用到發(fā)展中國(guó)家的政策研究。老發(fā)展經(jīng)濟(jì)學(xué)家是不承認(rèn)新古典經(jīng)濟(jì)學(xué)可以用于發(fā)展中國(guó)家，而新發(fā)展經(jīng)濟(jì)學(xué)家不僅認(rèn)為新古典經(jīng)濟(jì)學(xué)可以用于發(fā)展中國(guó)家，而且認(rèn)為發(fā)展經(jīng)濟(jì)學(xué)不能成為一個(gè)專門的學(xué)科。If the first generation of development economists was visionary anddedicated to grand theories and general strategies, the second generationwas almost moralistic, dedicated to a somber realism grounded onfundamental principles of neoclassical economics. Harberger could sayto the governments of developing countries, Economics is good foryouand by economics, he meant neoclassical analysis as the basisfor policymaking (Harberger 1993).Once it is recognized that individuals respond to incentives, andthat market failure is the result of inappropriate incentives ratherthan of nonresponsiveness, the separateness of development economicsas a field largely disappears. Instead, it bees an appliedfield, in which the tools and insights of labor economics, agriculturaleconomics, international economics, public finance and otherfields are addressed to the special questions and policy issues thatarise in the context of development. (Krueger 1986: 62 f)9(1) In accordance with neoclassical economic theory, the second generationmoved from highly aggregative models to disaggregatedmicrostudies in which the units of analysis were production units andhouseholds. (2) For offering policy advice, grand theories came to beviewed as less useful than highly specific applications. Microstudies,rather than the broader visionary models of the earlier period, couldprovide more direct policy implications for specific policies such as achange in tariffs or agricultural subsidies. (3) There was a marked change from a focus on the process of development to an emphasis on particular features of underdevelopment. (4) Quantitative analytical tools were used more extensively, especially for empirical analysis of microphenomena that were country specific, sector specific, or projectspecific. The greater availability of microdata sets allowed the modelingof household behavior and of human capital investments in educationand health.(5) The second generation, which was able to reflect on two or three decadesof development experience, recognized the increasing heterogeneity ofdeveloping countries and gave more attention to an explanation of differentialrates of country performance. Crosscountry econometric studiesof the determinants of economic growth multiplied. A parativeapproach was adop