# Is it possible to see in an equation if fixed effects are used in cross section regression?

I need to find out if multilateral resistance terms are accounted in an Gravity Equation, so Anderson and Wincoop (2003) says one method is to use Country Fixed effects.

So is it possible to see in a Gravity Equation like these for estimating in a a pooled time-series-cross-section regression, if country fixed effects are used?

Exports(I,J) = C+a11(D89)+a12(D91)+a13(D93)+a14(D95)+a15(D97) +b1(GDP(I))+b2(GDP(J))+c1(GDPPC(I))+c2(GDPPC(J)) +e1(DIST(I,J))+e2(REMOTE(I))+e3(REMOTE(J))+e4(CONTIG(I,J))+f(SL(I,J)) +dum1(PTA(I,J))+dum2(TREND PTA(I,J)) +dum3(NOPTA(I),PTA(J))+dum4(TREND NOPTA(I),PTA(J))

Here D are year dummies, and I know time fixed effects are used, which was explained in the working paper but not more. But I don't know if also Country fixed effects are used. Contig for common land border, Sl for same language, PTA if both are in PTA and so on.

• OK I think it is possible... There are no country specific effects used, only time effects. Commented Apr 17, 2018 at 20:38
• I am afraid that your question was ignored as not very clear. No source for the equation, no details of the reference, not very well written. I don't understand it either: if a particular report is not clear on what was done, we can't add detail unless (minute chance) one or more of us were the authors. Why not ask them? Commented Apr 18, 2018 at 8:36
• Srry, english is not my common language. Source is nber.org/papers/w7429. Commented Apr 18, 2018 at 8:49
• If for example country-pair effects and country effects are used, there would be no need of distance, remote, contiguity or language because they dont varying over time. This is what I learned from a paper Cheng and Wall (2005). And there is a need of country, and country-pair effects, because it is possible, that the variable PTA[I,J] suffers from unobserved time invariant heterogeneity. Sorry I never before did something with Paneldata, so i needed help. And if the question was unclear a comment were be nice so that i could try to say it better. Commented Apr 18, 2018 at 8:57
• Sorry your experience was not good here. I didn't notice this question when first posted: its title showed that it was not in my territory. We are all busy and filter what we answer or comment on in various ways. This isn't a help line where someone must answer: people often just move on when something isn't clear. For future questions, please note that bare name (date) references aren't informative except to people in exactly the same field as you. Commented Apr 18, 2018 at 9:14