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