Re: st: RE: Can't store estimates after logistic regression

[Edouard Betsem <edouardbetsem@gmail.com>]

Sorry Steve, à Mistake clicking the reply button instead of reply all.
Best

Edouard BETSEM, MD, PhD


On 30/06/2013 04:28, Steve Samuels wrote:
> Edouard:
>
> Please do not send me private messages asking for advice, except as the Statalist FAQ provide (i.e. for paid consultation). I'm not familiar with
> the other two commands.
>
>
> Steve
> On Jun 30, 2013, at 2:26 AM, Edouard Betsem wrote:
>
> Thanks, I tried both models and they are working.
> I also ran a -rocreg- and -rocregplot- model that returned a p value of 0.08
> The roccomp model returned a p value of 0.008
>
> Which one should I consider here?
>
> Edouard
>
>
> On 29/06/2013 09:33, Steve Samuels wrote:
> > Just a thought:
> >
> > Since you have models with single classification variables,
> > -logistic- isnt't strictly necessary. You can use
> > -roccomp- on any set of predictors, as long as higher
> > values of each are associated with higher risk of the
> > event.
> >
> > . corr foreign mpg
> > . corr foreign turn //note negative correlation
> > . gen rturn = -turn  // reverse turn
> > . roccomp foreign mpg rturn
> >
> > Higher values of predictions after -logistic- are always
> > associated with increased risk, so no reversals
> > are needed.
> >
> > ---------------------------
> >
> > Steve
> >
> > Ed:
> >
> > You probably want something like this:
> >
> > . sysuse auto, clear
> > . logistic foreign mpg
> > . predict p1
> > . logistic foreign turn
> > . predict p2
> > . roccomp foreign p1 p2
> >
> >
> > Steve
> >
> > On Jun 28, 2013, at 7:40 PM, Edouard Betsem wrote:
> >
> > Thanks Steve, I understand it better now. I got to go through some more readings.
> > Ed
> >
> >
> > On 28/06/2013 15:54, Steve Samuels wrote:
> > > Eduoard:
> > >
> > > If you do
> > >
> > > . des _est_mod1
> > >
> > > you will see the variable label: "esample() from estimates store".
> > > esample() just records whether the observation was used in the analysis
> > >
> > > It  not the kind of variable needed by -roccomp-, which has syntax:
> > >
> > > . rocommp refvar classvar
> > >
> > > According to the Manual:
> > >
> > > "The two variables refvar and classvar must be numeric. The reference
> > > variable indicates the true state of the observation, such as diseased
> > > and nondiseased or normal and abnormal, and must be coded as 0 and 1.
> > > The rating or outcome of the diagnostic test or test modality is
> > > recorded in classvar, which must be at least ordinal, with higher values
> > > indicating higher risk."
> > >
> > > In short -estimates- is irrelevant for running -roccomp-. I suggest that you
> > > reread the manual entry for -roccomp-.
> > >
> > > Steve
> > >
> > > On Jun 28, 2013, at 5:54 PM, Edouard Betsem wrote:
> > >
> > > It's still not working.
> > > by is not allowed here and using separate returned this error code
> > >
> > > [__00000E] not found
> > > r(111);
> > >
> > > I'm wondering if "roccomp" can be used with "estimates"
> > >
> > > I've even renamed the _est_mod1 to mod1. It's on the editor table but I don't know why Stata can't find it
> > >
> > >            logistic tma whoall
> > >            est store mod1
> > >            rename _est_mod1 mod1
> > >
> > >            logistic tma study_2
> > >            est store mod2
> > >            rename _est_mod2 mod2
> > >            roccomp tma _est_mod1 _est_mod2, graph summary
> > >
> > > the estimates variables return the value "1" for all my observations.
> > > Wish someone can help me solve this.
> > > Thanks
> > >
> > > Edouard BETSEM, MD, PhD
> > >
> > >
> > > On 28/06/2013 00:48, Bley N'Dede wrote:
> > > > I am not sure but may be you should try something like
> > > >
> > > > roccomp _est_mod1 _est_mod2, graph summary by(dis)
> > > > ________________________________________
> > > > From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of Edouard Betsem [edouardbetsem@gmail.coou should try m]
> > > > Sent: Friday, June 28, 2013 7:29 AM
> > > > To: statalist@hsphsun2.harvard.edu
> > > > Subject: st: Can't store estimates
> > > >
> > > > Hi,
> > > > I'm trying to use roccomp commande to compare AUC for two logistic
> > > > models. but stata won't store my estimates.
> > > >
> > > > here are the commande lines.
> > > >
> > > > * all counts with binary
> > > >              logistic dis ref
> > > >              est store mod1
> > > >
> > > >              logistic dis stud
> > > >              est store mod2
> > > >              roccomp dis mod1 mod2, graph summary
> > > >
> > > > and this is the message i have:
> > > >
> > > > variable mod1 not found
> > > > r(111);
> > > >
> > > > does anyone know the reason for this?
> > > > Best
> > > > Edouard
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Edouard BETSEM, MD, PhD
> > > >
> > > >
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