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Re: st: Time to event analysis OLS negative intercept, Survival Analysis


From   Reese Andorfer <[email protected]>
To   "[email protected]" <[email protected]>
Subject   Re: st: Time to event analysis OLS negative intercept, Survival Analysis
Date   Sat, 13 Jul 2013 22:58:36 +0200

Dear all,

Thank you for your replies. Predictor variables are a mix of binary,
categorial and continous variables, if that is of any help.

Best regards,
Reese

2013/7/13 Reese Andorfer <[email protected]>:
> Dear all,
>
> Thank you for your replies. Predictor variables are a mix of binary,
> categorial and continous variables, if that is of any help.
>
> Best regards,
> Reese
>
> Am Dienstag, 9. Juli 2013 schrieb Austin Nichols :
>
>> Reese Andorfer <[email protected]>:
>>
>> The log of a number between zero and one is negative, so you are
>> predicting that
>> duration is between 0 and 1 when all X vars are zero...
>> but OLS regression of a log y on X is not appropriate when y can equal
>> zero.
>>
>> See also
>>
>> http://blog.stata.com/2011/08/22/use-poisson-rather-than-regress-tell-a-friend/
>> and its inspiration
>> http://www.stata.com/meeting/boston10/boston10_nichols.pdf
>>
>> On Tue, Jul 9, 2013 at 5:28 PM, Reese Andorfer <[email protected]>
>> wrote:
>> > Dear all,
>> >
>> > My dependent variable is the duration up until to an event. I did Cox
>> > regressions for my models, which worked fine. Now, since I have
>> > uncensored
>> > data I ran OLS regressions ( dependent variable still the duration -
>> > altough I took the log) as a sort of robustness check, however I get now
>> > negative values for the intercepts, which kind of bugs me since I don't
>> > have an explanation for it. Any ideas on what I might be doing wrong ?
>> >
>> > Thank you,
>> > Best Reese
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