Elhanan Helpman

Quality Ladders in the Theory of Growth

We develop a model of repeated product improvements in a continuum of sectors. Each product follows a stochastic progression up a quality ladder. Progress is not uniform across sectors, so an equilibrium distribution of qualities evolves over time. But the rate of aggregate growth is constant. The growth rate responds to profit incentives in the R&D sector. We explore the welfare properties of our model. Then we relate our approach to an alternative one that views product innovation as a process of generating an ever-expanding range of horizontally differentiated products. Finally, we apply the model to issues of resource accumulation and international trade.

A Simple Theory of International Trade with Multinational Corporations

Using the idea that firm-specific assets associated with marketing, management, and product-specific R & D can be used to service production plants in countries other than the country in which these inputs are employed, I develop a simple general equilibrium model of international trade in which the location of plants in a differentiated product industry is a decision variable. The model is then used to derive predictions of trade pattern, volumes of trade, the share of intra-industry trade, and the share of intrafirm trade as functions of relative country size and differences in relative factor endowments.

Integration versus Outsourcing in Industry Equilibrium

We develop an equilibrium model of industrial structure in which the organization of firms is endogenous. Differentiated consumer products can be produced either by vertically integrated firms or by pairs of specialized companies. Production of each variety of consumer good requires a unique, specialized component. Vertically integrated firms can manufacture the components they need in the quantity and type that maximizes profits, but they face a relatively high cost due to diseconomies of scope. Specialized firms can produce at lower cost, but outsourcing imposes costs due to search frictions and imperfect contracting. We study the equilibrium mode of organization when inputs are fully or partially specialized. We consider how the degree of competition in the industry, the nature of the search technology, the division of bargaining strength between intermediate and final producers, and the sensitivity of manufacturing costs to input characteristics affect the equilibrium organizational form.

International trade in the presence of product differentiation, economies of scale and monopolistic competition: A Chamberlin-Heckscher-Ohlin approach

Abstract The paper presents a generalization of the Heckscher-Ohlin theory by admitting the existence of sectors in which there is monopolistic competition. The structure of preferences is based on Lancasters work. It is shown without requiring homotheticity in the production of differentiated products that the intersectoral pattern of trade can be predicted from factor endowments but not from pre-trade commodity prices or factor rewards, except under special circumstances. It is also shown how the share of intra-industry trade is related to differences in income per capita and how the volume of trade depends on differences in income per capita and relative country-size Other empirical implications are also discussed.

Imperfect competition and international trade: Evidence from fourteen industrial countries

Abstract Three hypotheses that emerge from a theoretical model are discussed. Two of them concern the behavior of the share of intraindustry trade while the third concerns the volume of trade. One is that in cross-country comparisons the larger the similarity in factor composition, the larger the share of intraindustry trade. The second is that in time series data the more similar the factor composition of a group of countries becomes over time, the larger the share of intraindustry trade within the group. The third is that changes over time in relative country size can explain the rising trade-income ratio. All three hypotheses are consistent with the data. J. Japan. Int. Econ., March 1987, 1(1), pp. 62–81. Department of Economics, Tel Aviv University, Ramat-Aviv, Tel Aviv 69978, Israel.

Trade, FDI, and the Organization of Firms

New developments in the world economy have triggered research designed to better understand the changes in trade and investment patterns, and the reorganization of production across national borders. Although traditional trade theory has much to offer in explaining parts of this puzzle, other parts required new approaches. Particularly acute has been the need to model alternative forms of involvement of business firms in foreign activities, because organizational change has been central in the transformation of the world economy. This paper reviews the literature that has emerged from these efforts. The theoretical refinements have focused on the individual firm, studying its choices in response to its own characteristics, the nature of the industry in which it operates, and the opportunities afforded by foreign trade and investment. Important among these choices are organizational features, such as sourcing strategies. But the theory has gone beyond the individual firm, studying the implications of firm behavior for the structure of industries. It provides new explanations for trade structure and patterns of FDI, both within and across industries, and has identified new sources of comparative advantage.

Electoral Competition and Special Interest Politics

We study the competition between two political parties for seats in a parliament. The parliament will set two types of policies: ideological and non-ideological. The parties have fixed positions on the ideological issues, but choose their non-ideological platforms to attract voters and campaign contributions. In this context, we ask: How do the equilibrium contributions from special interest groups influence the platforms of the parties? We show that each party is induced to behave as if it were maximizing a weighted sum of the aggregate welfares of informed voters and members of special interest groups. The party that is expected to win a majority of seats caters more to the special interests.

Quality Ladders and Product Cycles

We develop a two-country model of endogenous innovation and imitation in order to study the interactions between these two processes. Firms in the North race to bring out the next generation of a set of technology-intensive products. Each product potentially can be improved a countably infinite number of times, but quality improvements require the investment of resources and entail uncertain prospects of success. In the South, entrepreneurs invest resources in order to learn the production processes that have been developed in the North. All R&D investment decisions are made by forward looking, profit maximizing entrepreneurs. The steady-state equilibrium is characterized by constant aggregate rates of innovation and imitation. We study how these rates respond to changes in the sizes of the two regions and to policies in each region to promote learning.

Endogenous Product Cycles

We construct a model of the product cycle featuring endogenous innovation and endogenous technology transfer. Competitive entrepreneurs in the North expend resources to bring out new products whenever expected present discounted value of future oligopoly profits exceeds current product development costs. Each Northern oligopolist continuously faces the risk that its product will be copied by a Southern imitator, at which time its profit stream will come to an end. In the South, competitive entrepreneurs may devote resources to learning the production processes that have been developed in the North. There too, costs (of reverse engineering) must be covered by a stream of operating profits. We study the determinants of the long-run rate of growth of the world economy, and the long-run rate of technological diffusion. We also provide an analysis of the effects of exogenous events and of public policy on relative wage rates in the two regions.

Increasing returns, imperfect markets, and trade theory

Publisher Summary This chapter discusses two major issues: explanations of trade patterns and gains from trade. The classical traditions were mainly concerned with gains from trade and other welfare effects. The theory of international trade is surveyed in the presence of economies of scale and monopolistic competition, with an emphasis on predictions of trade patterns and gains from trade. The main ingredient of this logic is that the allocation of productive resources is guided in every country by the reward level of every sectors employed combination of factors of production. Economies of scale, which arise from conglomeration or public intermediate inputs, seem to be country specific, and due to transportation costs within-industry specialization in some stages of production are countries specific. It seems, therefore, that the size of a domestic industry plays a role in the determination of external economies of scale. But it is also clear that some sources of these scale economies affect more than a single industry, which implies cross-industry spillovers of external economies of scale. The chapter provides an overview on the general model of trade in homogeneous products when there are variable returns to scale and free entry into industries.