楼主可以改进一下模型。

怎么改进，盼指明方向。 2# wangyantaoking

可以考虑，个人根据研究添加变量和一般多元回归一样的，不光是fdi,汇率等其它宏观变量也可加进去。但引力模型是推导出来的，其普通型，增强型，动态型，随机型，二（三）元边际型，产品层次型（ds ,ek)都有相应的推导。建议大家阅读下列文献：
Anderson J.E. (1979) “ATheoretical Foundation for the Gravity Equation”, AER,
69(1):106-116

Anderson J. and E. Van Wincoop (2003) “Gravity with Gravitas: A solution to the
Border Puzzle” AER, 93:170-192
Baldwin R. and D. Taglioni (2006) “Gravity for Dummies and Dummies for Gravity
Equations”, NBER WP 12516

Baum Christopher, 2006, An Introduction to Modern Econometrics Using Stata, Stata
Press  

Bergstarnd J.H. (1990) “The Heckscher-Ohlin-Samuelson model,the Linder
Hypothesis, and the Determinants of Bilateral Intra-industry Trade” Economic
Journal, 100(4):1216-1229

Bond Stephen, 2002, “Dynamic panel data models: a guide to microdata methods and
practice”, Technical Report CWP09/02, Institute for Fiscal Studies

Deardoff (1998)”Determinants of Bilateral Trade: Does Gravity Work in a
Neoclassical Framework?” in J.A. Frankel (ed.) The Regionalization of the World
Economy, Chicago: University of Chicago Press

Evenett S. and W. Keller (2002) “On Theories Explaining the Gravity Equation”,
Journal of Political Economy, 110:281-316

Feenstra, R.(2004) Advanced International Trade, MIT Press

Head K. (2003)”Gravity for Beginners”, mimeo, University British Columbia

Helpman, Melitz and Rubinstain (2008) “Trading Partners and Trading Volumes”,
Quarterly Journal of Economics

J.M.C Santos Silva and S. Tenreyro, (2006), “The Log of Gravity”, Review of
Economics and Statistics

Westerlund J. and F. Wilhelmsson (2006) “Estimating the gravity Model without
Gravity Using Panel Data”, at www.nek.lu.se

现有理论模型基本都是基于静态进行推导，因此不会有时间滞后项；如果使用的是面板数据，是否可以使用是一个可以探讨的问题。

顶，求高手指教阿，面板数据用引力模型，就是纯贸易量，可不可以搞时间滞后呢？？？？求高手大家讨论阿