[R] clogit comparison between Stata and R

[David Hugh-Jones]

Hi Thomas

Sorry to bug you again after 6 months! I just wondered if there is a
simple way to find the N after dropping groups with invariant outcomes
- I am reading coxph.object and the structure of the returned object,
but nothing jumps out at me.

With best wishes,
David Hugh-Jones


On 9 July 2009 14:37, Thomas Lumley <tlumley at u.washington.edu> wrote:
> On Wed, 8 Jul 2009, David Hugh-Jones wrote:
>
>> Hello all
>>
>> I'm moving back and forth between stata and R at the moment - of course,
>> using R whenever possible :-)
>>
>> I'm running conditional logits on some panel data and I get slightly
>> different results and different N in the two programs.
>
> That's probably because you are using method="approximate" in R.
>
>>
>> I understand why Stata is dropping the groups with all outcomes the
>> same...
>> this is inevitable in a conditional logit, right?
>
> Yes.
>
>> Is R doing the same?
>
> Yes.
>
>        -thomas
>