I have this panel data set where the number of records for a panel differs greatly, e.g. e.g. a case might have anywhere from 2 to 50 records. For each record, I have a variable that is coded 1 if this is the highest scoring record for that panel member, 0 otherwise. I want to run an xtlogit or melogit analysis with this as the dependent variable. That is, I want to examine what determines a respondent's most successful record.
The problem is, with larger panels, the biggest reason a record isn't ranked #1 is because there are more records that could be #1. e.g. if you only have 2 records, there is a 50% chance for each record to be ranked #1, but with 50 records it is only a 2% chance.
So the question is, how best to control for panel size? If I were doing poisson, I think I would use the exposure option, e.g. exposure(nrecs); or the offset option, e.g. offset(ln_nrecs). Should I do something similar in xtlogit, e.g. include the log of nrecs as an explanatory variable? Or is there some more appropriate way to control for the fact that panels do not have the same number of records?
Unfortunately, I cannot share any of the data at this time, but hopefully my explanation of the problem is clear enough. I would imagine that issues caused by differences in panel size have come up in other situations.
The problem is, with larger panels, the biggest reason a record isn't ranked #1 is because there are more records that could be #1. e.g. if you only have 2 records, there is a 50% chance for each record to be ranked #1, but with 50 records it is only a 2% chance.
So the question is, how best to control for panel size? If I were doing poisson, I think I would use the exposure option, e.g. exposure(nrecs); or the offset option, e.g. offset(ln_nrecs). Should I do something similar in xtlogit, e.g. include the log of nrecs as an explanatory variable? Or is there some more appropriate way to control for the fact that panels do not have the same number of records?
Unfortunately, I cannot share any of the data at this time, but hopefully my explanation of the problem is clear enough. I would imagine that issues caused by differences in panel size have come up in other situations.
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