Hello all.

I am trying to estimate a granular commuting gravity equation (As described in http://www.jdingel.com/research/DingelTintelnotSEGS.pdf , estimated model in pages 15-16).

I have a cross-sectional commuting matrix which contains roughly 2600 regions, and I am interested both in the coefficent of commuting time, and the origin and destination fixed effects.

I estimate the following model:
Code:
ppmlhdfe commutes dist, absorb(origin_code dest_code) tolerance(1.0e-10)
I'm concerned about the estimation of the origin and destination fixed effects, this concens rises from the following statement in the ppmlhdfe help file:
Code:
    - To save the estimates specific absvars, write newvar=absvar.
    - However, be aware that estimates for the fixed effects are generally inconsistent and not econometrically identified.
I was wondering if:
1. Is there a way to consistently estimate the fixed effects using ppmlhdfe?
2. I am replicating the methodolgy in the working paper linked above. The paper uses ppmlhdfe for estimation, and reports destination fixed effects (page 19). Am I mis-specifying the equation or missing something else?

Thanks in advance,
Gal