Pierola Castro, Martha Denisse

Trade and Integration Team, Development Research Group, The World Bank
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International economics, Export development, Firm-level analysis of trade
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Trade and Integration Team, Development Research Group, The World Bank
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Last updated: January 31, 2023
Martha Denisse Pierola is an Economist in the Trade and International Integration Unit of the Development Research Group of the World Bank. She has published several papers on export growth and exporter dynamics and co-created the Exporter Dynamics Database –the first-ever global database on exporter growth and dynamics, based on firm-level export data. Her research studies the role of large exporters in driving trade patterns and export growth; and examines how exporter behavior varies with the stage of development. She was the leader of the team conducting the World Bank study on trade, competitiveness and regional integration in Zimbabwe. She has worked on issues related to regionalism, trade costs and trade and productivity. Before joining the World Bank, she worked as an economist for the Peruvian Government (INDECOPI) and also consulted for the private sector and other international organizations. She has a PhD in economics from the Graduate Institute of International Studies in Geneva, Switzerland and a Master of International Law and Economics from the World Trade Institute in Bern, Switzerland.
Citations 95 Scopus

Publication Search Results

Now showing 1 - 10 of 14
  • Publication
    Patterns of Export Diversification in Developing Countries : Intensive and Extensive Margins
    (World Bank, Washington, DC, 2008-01) Amurgo-Pacheco, Alberto; Pierola, Martha Denisse
    This paper uses highly disaggregated trade data to investigate geographic and product diversification patterns across a group of developing nations for the period from 1990 to 2005. The econometric investigation shows that the gravity equation fits the observed differences in diversification across nations. The analysis shows that exports at the intensive margin account for the most important share of overall trade growth. At the extensive margin, geographic diversification is more important than product diversification, especially for developing countries. Taking part in free trade agreements, thereby reducing trade costs, and trading with countries in the North are also found to have positive impacts on export diversification for developing countries.
  • Publication
    The Intensive Margin in Trade
    (World Bank, Washington, DC, 2018-10) Klenow, Peter J.; Fernandes, Ana M.; Meleshchuk, Sergii; Rodriguez-Clare, Andres; Pierola, Martha Denisse
    Is the variation in bilateral trade flows across countries primarily due to differences in the number of exporting firms (the extensive margin) or in the average size of an exporter (the intensive margin)? And how does this affect the estimation and quantitative implications of the Melitz (2003) trade model? The benchmark Melitz model with Pareto-distributed firm productivity and fixed costs of exporting, predicts that, conditional on the fixed costs of exporting, all variation in exports across trading partners should occur on the extensive margin. This paper subjects this theoretical prediction to a reality check drawing upon the World Bank's Exporter Dynamics Database (EDD) which has firm-level exports from 50 developing countries to all destinations. Around 50 percent of the variation in exports across trading partners is shown to be along the intensive margin, contradicting the benchmark Melitz-Pareto model. The paper finds that moving from a Pareto to a lognormal distribution of firm productivity allows the Melitz model to successfully match the role of the intensive margin evident in the EDD. The paper then studies the implications of our findings for quantitative trade theory. Using likelihood methods and the EDD, a generalized Melitz model with a joint lognormal distribution for firm productivity, fixed costs and demand shifters is estimated, and exact hat algebra is used to quantify the counterfactual effects of a decline in trade costs on trade flows and welfare in the estimated model. Finally, these effects are compared to those that would be predicted by the Melitz-Pareto model, with the Pareto shape parameter chosen to match the average trade elasticity implied by the estimated Melitz-lognormal model. The paper shows that the effects on welfare turn out to be quite close to those in the standard Melitz-Pareto model even though the effects on trade flows remain different.
  • Publication
    The Origins and Dynamics of Export Superstars
    (Published by Oxford University Press on behalf of the World Bank, 2020-02) Freund, Caroline; Pierola, Martha Denisse
    Export superstars are important for export growth and diversification and are typically born large. Firm-level data on manufacturing trade from 32 developing countries show that the top five exporters account for on average nearly one-third of exports, 47 percent of export growth, and a third of the growth due to export diversification over a five-year period. Within countries and industries, export growth is positively correlated with the share of exports in the top five firms. Most of the top five exporters were already large five (or eight) years ago or are new firms; it is rare for these export superstars to emerge from the bottom half of the distribution of firm sizes. For countries where detailed data exist, superstars are producers, not traders, and are primarily foreign owned.
  • Publication
    Success and Failure of African Exporters
    (2011-05-01) Cadot, Olivier; Iacovone, Leonardo; Pierola Castro, Martha Denisse; Rauch, Ferdinand
    Using a novel dataset with transactions level exports data from four African countries (Malawi, Mali, Senegal and Tanzania), this paper uncovers evidence of a high degree of experimentation at the extensive margin associated with low survival rates, consistent with high and middle income country evidence. Consequently, the authors focus on the questions of what determines success and survival beyond the first year and find that survival probability rises with the number of firms exporting the same product to the same destination from the same country, pointing towards the existence of cross-firm synergies. Accordingly the evidence is consistent with the hypothesis that those synergies may be driven by information spillovers. More intuitively and consistently with multi-product firms models, the analysis also finds that firms more diversified in terms of products, but even more in terms of markets, are more likely to be successful and survive beyond the first year.
  • Publication
    Exporter Behavior, Country Size and Stage of Development: Evidence from the Exporter Dynamics Database
    (World Bank, Washington, DC, 2015-10) Fernandes, Ana M.; Freund, Caroline; Pierola, Martha Denisse
    This paper presents new data on the micro structure of the export sector for 45 countries and studies how exporter behavior varies with country size and stage of development. Larger countries and more developed countries have more exporters, larger exporters, and a greater share of exports controlled by the top 5 percent. The extensive margin (more firms) plays a greater role than the intensive margin (average size) in supporting exports of larger countries. In contrast, the intensive margin is relatively more important in explaining the exports of richer countries. Exporter entry and exit rates are higher and entrant survival is lower at an early stage of development. The paper discusses the results in light of trade theories with heterogeneous firms and the empirical literature on resource allocation, firm size, and development. An implication from the findings is that developing countries export less because the top of the firm-size distribution is truncated.
  • Publication
    Export Competitiveness: Why Domestic Market Competition Matters
    (World Bank, Washington, DC, 2015-06) Goodwin, Tanja; Pierola, Martha Denisse
    This review of the empirical literature shows that industries with more intense domestic competition will export more. Competition law enforcement can be traced to export performance and is complementary to trade reforms. Pro-competition market regulation that reduces restrictions and promotes competition, where it is viable, is an important determinant for trade. The elimination of barriers to entry and rivalry, and a level playing field in upstream sectors contributes to export competitiveness in downstream manufacturing sectors. In some sectors, effective competition policy can directly lower trade costs.
  • Publication
    Trade in Zimbabwe: Changing Incentives to Enhance Competitiveness
    (Washington, DC: World Bank, 2015-05-22) Newfarmer, Richard; Pierola, Martha Denisse
    In Zimbabwe trade has been a driver of economic growth, rising incomes, and progressive empowerment of Zimbabweans through rising standards of living and the promise of better jobs. Since 1980, through good years and bad years, increases in exports have been positively associated with increases in national income. Zimbabwe's location and resource base, together with a low-cost but relatively well educated labor force, have endowed it with a naturally high trade ratio built on a diversified base that facilitates using trade as an engine of growth. While trade volumes have rebounded smartly from the deep recession of 2007-2008, these do not offset other worrisome longer-term trends: 1) export growth during the last decade has been lackluster and failed to drive high growth; 2) agricultural exports, other than tobacco, have lost their once dominant role in the region, and are no longer a source of diversification; 3) manufacturing has withered in a continuing secular decline; and 4) Zimbabwe's export basket has become less diversified and more dependent on a narrow range of mineral and, to a lesser extent, agricultural products. In short, exports have become less diversified, less-technologically sophisticated, and less labor-intensive, and ever more dependent on a few large mining activities to provide foreign exchange and employment. This report traces the roots of this poor performance to several policy issues: poor predictability of macroeconomic policy and economic governance has created an unfavorable climate for private investment and trade; a tariff structure that dampens export profitability; industrial policies (indigenization policy in particular) that undermine investor confidence and inhibits private investment; and finally, competition-limiting policies toward services that limit connectivity of Zimbabweans and raise trade costs. The good news arising from the study is that the remedies for these policy shortcomings lie in Zimbabwean hands. If the government were to adopt reforms that reconfigure economy-wide incentives and trade and industrial policies, it could promote sustained growth, economic diversification and empowerment of poor people.
  • Publication
    Pathways to African Export Sustainability
    (Washington, DC: World Bank, 2012-07-02) Brenton, Paul; Pierola, Martha Denisse
    This report provides tentative leads toward such policy prescriptions, based on an overview of the empirical evidence. Chapter one sets the stage by putting Africa's export-survival performance into perspective and proposing a framework that will guide the interpretation of empirical evidence throughout the report. Chapter two covers country-level determinants of export sustainability at origin and destination, including the exporting country's business environment. Chapter three explores some of the firm-level evidence on what drives export sustainability, including uncertainty, incomplete contracts, learning, and networks. Finally, chapter four offers tentative policy implications. The main conclusions from this overview of the causes of Africa's low export sustainability should be taken with caution both because of the complexity of the issue and because of the very fragmentary evidence on which the overview is based. The author should be more cautious in drawing policy implications, as hasty policy prescriptions are the most common trap into which reports of this kind can fall. A first, solid conclusion is that the author needs substantial additional work on the nature and causes of low export survival rates in developing countries to determine the path to high export sustainability.
  • Publication
    Export Entrepreneurs : Evidence from Peru
    (2010-08-01) Freund, Caroline; Pierola, Martha Denisse
    This paper examines firm entry and survival in exporting, and in products and markets not previously served by any domestic exporters. The authors use data on the nontraditional agriculture sector in Peru, which grew seven-fold from 1994 to 2007. They find tremendous firm entry and exit in the export sector, with exits more likely after one year and among firms that start small. There is also significant entry and exit in new markets. In contrast, such trial and error in new products is rare. New products are typically discovered by large experienced exporters and there is increased entry after products are discovered. The results imply that high sunk costs of entry are of concern for product discovery, especially for products that are not consumed domestically. In contrast, the tremendous entry and exit in exporting and in new markets suggests that initial sunk costs are relatively low. The authors develop a model that explains how entrepreneurs decide to export and to develop new export products and markets when there are sunk costs of discovery and uncertainty about idiosyncratic costs. The model explains many features of the data.
  • Publication
    Export Surges : The Power of a Competitive Currency
    (World Bank, Washington, DC, 2008-10) Freund, Caroline; Pierola, Martha Denisse
    How can countries stimulate and sustain strong export growth? To answer this question, the authors examine 92 episodes of export surges, defined as significant increases in manufacturing export growth that are sustained for at least seven years. They find that export surges in developing countries tend to be preceded by a large real depreciation-which leaves the exchange rate significantly undervalued-and a reduction in exchange rate volatility. In contrast, in developed countries, the role of the exchange rate is less pronounced. The authors examine why the exchange rate is so important in developing countries and find that the depreciation leads to a significant reallocation of resources in the export sector. In particular, depreciation generates more entries into new export products and new markets, and the percentage of new entries that fail after one year declines. These new products and new markets are important, accounting for 25 percent of export growth during the surge in developing countries. The authors argue that maintaining a competitive currency leads firms to expand the product and market space for exports, inducing a large reorientation of the tradable sector.