Re: st: Non omitted variables with individual fixed effects

[Estrella Gomez <estrellastata@gmail.com>]

Yes, I expect Stata to drop gdp_part because is constant within
groups, and so it is i.part. I expect this two variables to be
perfectly collinear; that's why I think that Stata should drop
gdp_part

Thanks,
Estrella

2013/11/29 Nick Cox <njcoxstata@gmail.com>:
> Would you expect Stata to drop a predictor that is an indicator
> variable because it is constant within groups?
>
> I don't think we can comment otherwise on whether the model is
> correctly specified. Even economists would have to guess hard to work
> out what your variables are.
>
> Nick
> njcoxstata@gmail.com
>
>
> On 29 November 2013 11:01, Estrella Gomez <estrellastata@gmail.com> wrote:
>> Dear statalisters
>>
>> I am running a regression on a cross section basis. I use country
>> specific fixed effects and, at the same time, I introduce country
>> specific variables in the regression:
>>
>> xi: reg logCBT log_dist comlang_off  gdp_part i.part i.decl , robust
>>
>> where decl and part are the variables identifying partner and
>> declarant countries, and gdp_part is the GDP of the partner
>>
>> My question is: why is gdp_part not excluded? This variable is
>> constant for the partner and I was expecting Stata to drop it. Is the
>> command incorrectly specified?
>>
>> Thanks a lot,
>> Estrella
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>> *   http://www.ats.ucla.edu/stat/stata/
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/faqs/resources/statalist-faq/
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/