期刊名称：DIW Diskussionspapiere / Deutsches Institut für Wirtschaftsforschung, Berlin
出版年度：2007
卷号：2007
出版社：Deutsches Institut für Wirtschaftsforschung, Berlin
摘要：This study compares two alternative approaches to estimate parameters in gravity
equations. We compare the traditional OLS approach applied to the log-linear
form of the gravity model with the Poisson Quasi Maximum Likelihood (PQML)
estimation procedure applied to the non-linear multiplicative specification of
the gravity model. We use the trade flows for all products, for all
manufacturing products as well as for manufacturing products broken down by
three-digit ISIC Rev.2 categories. We base our conclusions on the generalised
gravity model of Bergstrand (1989) that allows us to investigate differences in
factor-proportions and home-market effects at the industry level. In addition,
we compare the effects of other explanatory variables such as exporter and
importer total income, distance, preferential trade agreements, common border,
historical ties, and common language on the volume of trade. Our study provides
comprehensive evidence on likely qualitative and/or quantitative differences in
the values of estimated coefficients as a result of application of an
alternative estimation method. Our main conclusion is that both estimation
results as well as results of the regression misspecification tests provide
supporting evidence for the PQML estimation approach over the OLS estimation
method.
