st: Panel data

[Alexander James <alexandre_lille-paris@hotmail.com>]

Dear Statalist members,

 

 

I am working on a database that has firm year observations. Each observation regards the degree of familiarity that a firm has with a new acquired technology. Accordingly the dependent variable measures the number of new products released in year t2. 

 

 

I am trying to run a FE or RE model capturing the effects of familiarity on the dependent variable (Probably a negative binomial). However, the problem is that I have multiple observations per year. In other words, the same firm may acquire more than one technology in the same year, that will have different degrees of familiarity. 

 

 

When I try to run the xtset firm_id year, I get the message repeated time values within panel. I read some topics explaining how to correct in case it is a mistake, but in my setting that is how the data really is. 

 

 

Would someone have any suggestion how to approach this issue?

 

 

Best Regards,

 

 

Alexandre James 		 	   		  
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