Re: [R] stepwise selection for conditional logistic regression

2012-02-22 Thread Frank Harrell
Stepwise variable selection is an invalid statistical method. Who or which book recommended it? Frank Subha P. T. wrote > >  Hi, > > Is there any function available to do stepwise selection of variables in > Conditional(matched) logistic regression( clogit)? step, stepwise  etc are > failing in

Re: [R] stepwise selection for conditional logistic regression

2012-02-22 Thread David Winsemius
On Feb 22, 2012, at 12:03 AM, Subha P. T. wrote: Hi David My data set has about 20 significant variables and step function with logistic regression is working fine( in R-commander). I tried to get conditional logistic by introducing the stratum variable and clogit. The clogit is not conv

Re: [R] stepwise selection for conditional logistic regression

2012-02-21 Thread Subha P. T.
Hi David My data set has about 20 significant variables and  step function with logistic regression is working fine( in R-commander). I tried to get conditional logistic by introducing the stratum variable and clogit. The clogit is not converging but is giving the summary of the model. When step

Re: [R] stepwise selection for conditional logistic regression

2012-02-21 Thread Subha P. T.
 Thanks Steve.  From: Steve Lianoglou To: David Winsemius ject.org> Sent: Friday, February 17, 2012 9:27 PM Subject: Re: [R] stepwise selection for conditional logistic regression Also, when you're doing reading through David's suggestions:

Re: [R] stepwise selection for conditional logistic regression

2012-02-21 Thread Subha P. T.
Thanks Weidong  for your help.I had earlier tried Step AIC also but no use. Trying other options as suggested by the R-group.    Subha [[alternative HTML version deleted]] __ R-help@r-project.org mailing list h

Re: [R] stepwise selection for conditional logistic regression

2012-02-17 Thread Steve Lianoglou
Also, when you're doing reading through David's suggestions: On Fri, Feb 17, 2012 at 10:41 AM, David Winsemius wrote: [snip] > Stepwise procedures are supported somewhat grudgingly on r-help. You ought > to read some of the critical comments about stepwise procedures in the > Archives: > > http:/

Re: [R] stepwise selection for conditional logistic regression

2012-02-17 Thread David Winsemius
On Feb 17, 2012, at 2:10 AM, Subha P. T. wrote: Hi, Is there any function available to do stepwise selection of variables in Conditional(matched) logistic regression( clogit)? step, stepwise etc are failing in case of conditional logistic regression. "Failing" is open to a variety

Re: [R] stepwise selection for conditional logistic regression

2012-02-17 Thread Weidong Gu
stepAIC works for an object of clogit. Weidong Gu On Fri, Feb 17, 2012 at 2:10 AM, Subha P. T. wrote: > > >  Hi, > > Is there any function available to do stepwise selection of variables in > Conditional(matched) logistic regression( clogit)? step, stepwise  etc are > failing in case of condit

[R] stepwise selection for conditional logistic regression

2012-02-16 Thread Subha P. T.
 Hi, Is there any function available to do stepwise selection of variables in Conditional(matched) logistic regression( clogit)? step, stepwise  etc are failing in case of conditional logistic regression. Please help.  Thanks P.T. Subha [[alternative HTML version deleted]] _