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Preferential Trade Agreements and the Margins of Agricultural Trade Growth. Shuwen Duan and Jason H. Grant, AAEC Seminar Feb. 22, 2013. Trade growth in dollar difference. Motivation . Gap in the literature Krugman (1981): over-estimate the extensive margin
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Preferential Trade Agreements and the Margins of Agricultural Trade Growth Shuwen Duan and Jason H. Grant, AAEC Seminar Feb. 22, 2013
Motivation • Gap in the literature • Krugman (1981): over-estimate the extensive margin • Armington(1996): extensive margin not considered • This study is focused on two research questions: • How important are the extensive and intensive margins in agricultural trade growth? • Do trade policies (i.e., Regional Trade Agreements (RTAs)) systematically influence the margins of trade?
Main Results • Extensive margin account for 30% of agricultural trade growth on average. • RTAs influence trade through different impact on the two margins.
Related literature and Contribution • Helpman, Melitz and Rubinstein(2008) • Selection bias and firm heterogeneity • Silva and Tenreyro (2006) & Liu(2009) • Pseudo-Poisson Maximum Likelihood • Hummels and Klenow(2006) • extensive and intensive margin index • Baier, Bergstrand and Feng(2012) • Found positive effect of Economic Integration Agreements on trade margins
II. Hummels and Klenow decomposition =(2)/(3) =(1)/(2)
Empirical estimation • Traditional gravity equation with FE effects • PPML estimation for two margin subgroups • Gravity-like estimation for HK margin indices
Data • Trade flow: • SITC Rev. 2 data: 1976-2010, • 101 countries • 147 agricultural products for 20 industries • 360,000 obs. • GDP • CEPII • RTA • From WTO • 102 RTAs
Results(1): PPML with margin subgroups *p < 0.05, **p < 0.01, ***p < 0.001. Dependent variables are bilateral trade value in levels. Remoteness index is included to account for multilateral price resistance terms and are not reported here. Year is time trend variable. Countrypair-Fixed Effects included but not reported.
Results(2): HK indices estimation *p < 0.05, **p < 0.01, ***p < 0.001 Remoteness index is included to account for multilateral price resistance terms and are not reported here. Year is time trend id. Pair-FE included but not reported.
Conclusions and implication • For 1976-2010, extensive margin growth is a significant part of agricultural trade growth. • On average, RTAs have positive effect in increasing countries’ export product varieties. • RTA membership is more effective in increasing the intensive margin of trade relative to extensive margin
Future work • Robustness check using different & longer base periods • Decompositions & estimations by industries • Removing potential price (inflation) effects from intensive margin • Duration of the extensive margin and, • At what point does the extensive margin become the intensive margin?