Hi,
I'm analyzing patent data for my thesis. I have a dataset with unique patents from 1999-2004, so no duplicates. I'd like to run two different regressions with two fixed effects. The first fixed effect is a year fixed effect, from 1999 until 2004. The second is a regional fixed effect based on the CBSA location of the first inventor of the patent. But I have my doubts on the way to execute it.
1st regression: poisson regression( because it is a count data variable)
Number of inventors in patent = indepvar+ Year fixed effect + regional fixed effect
2nd regression: lineair regression
Depvar(i.e. a probability) = indepvar+ Year FE+ regional FE
If my research is right there are 2 different ways of setting the fixed effect:
1) adding i. :
poisson depvar indepvar i.year i.cbsa
regression depvar indepvar i.year i.cbsa
2) via panel data:
xtset cbsa year
xtpoisson depvar indepvar year cbsa, fe
xtreg depvar indepvar year cbsa, fe
My questions:
-is there a preference between the 2 possibilities? should I expect a difference in the outcome between the 2? for example on Rsquared or significance
-I'm I allowed to set it as panel data? The patent-id is only included in the data set once, not reoccurring throughout the years
Thanks
Ludo
I'm analyzing patent data for my thesis. I have a dataset with unique patents from 1999-2004, so no duplicates. I'd like to run two different regressions with two fixed effects. The first fixed effect is a year fixed effect, from 1999 until 2004. The second is a regional fixed effect based on the CBSA location of the first inventor of the patent. But I have my doubts on the way to execute it.
1st regression: poisson regression( because it is a count data variable)
Number of inventors in patent = indepvar+ Year fixed effect + regional fixed effect
2nd regression: lineair regression
Depvar(i.e. a probability) = indepvar+ Year FE+ regional FE
If my research is right there are 2 different ways of setting the fixed effect:
1) adding i. :
poisson depvar indepvar i.year i.cbsa
regression depvar indepvar i.year i.cbsa
2) via panel data:
xtset cbsa year
xtpoisson depvar indepvar year cbsa, fe
xtreg depvar indepvar year cbsa, fe
My questions:
-is there a preference between the 2 possibilities? should I expect a difference in the outcome between the 2? for example on Rsquared or significance
-I'm I allowed to set it as panel data? The patent-id is only included in the data set once, not reoccurring throughout the years
Thanks
Ludo
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