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st: RE: RE: -by- with -binreg-


From   Lee Sieswerda <Lee.Sieswerda@tbdhu.com>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   st: RE: RE: -by- with -binreg-
Date   Wed, 4 Dec 2002 16:15:32 -0500

Thanks, Nick. That -cmd- option is handy. You gotta love those undocumented
options. The -by- works perfectly using -glm-.
Best,
Lee Sieswerda


> -----Original Message-----
> From:	Nick Winter [SMTP:nwinter@policystudies.com]
> Sent:	Wednesday, December 04, 2002 3:44 PM
> To:	statalist@hsphsun2.harvard.edu
> Subject:	st: RE: -by- with -binreg-
> 
> Looking at the ado code for -binreg-, it seems that -binreg- is a
> wrapper for -glm-, and that the call to -glm- does not preserve the "by
> varlist:" that you specify.
> 
> This should be a quick thing for SstataCorp to fix.  In the mean time,
> you can just call -glm- directly, which does properly support "by
> varlist:".  The (undocumented?) "cmd" option of -binreg- seems to tell
> you the necessary -glm- syntax.
> 
> Nick Winter
> 
> > -----Original Message-----
> > From: Lee Sieswerda [mailto:Lee.Sieswerda@tbdhu.com] 
> > Sent: Wednesday, December 04, 2002 3:31 PM
> > To: Statalist (E-mail)
> > Subject: st: -by- with -binreg-
> > 
> > 
> > Dear Statalisters:
> > For some reason I cannot get -by- to work with -binreg-. I 
> > can get around
> > the problem using -if-, but according to the manual I should 
> > be able to use
> > -by-. Here is my log:
> > 
> > . table pre_post sex, c(mean q7cat)
> > 
> > ------------------------------
> >           |        sex        
> >  pre_post |        F         M
> > ----------+-------------------
> >       pre | .3238095  .4953271
> >      post |       .6  .6296296
> > ------------------------------
> > 
> > * Both sexes together
> > . binreg q7cat pre_post, rd cluster(id)
> > 
> > Iteration 1 : deviance =  570.9529
> > Iteration 2 : deviance =  570.9529
> > 
> > Residual df  =       423                                No. of obs =
> > 425
> > Pearson X2   =       425                                Deviance   =
> > 570.9529
> > Dispersion   =  1.004728                                Dispersion =
> > 1.349771
> > 
> > Bernoulli distribution, identity link
> > Risk difference coefficients
> >                                (standard errors adjusted for 
> > clustering on
> > id)
> > --------------------------------------------------------------
> > --------------
> > --
> >              |             Semi-Robust
> >        q7cat |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .2046461   .0391639     5.23   0.000     .1278862
> > .281406
> >        _cons |   .2057312   .0651479     3.16   0.002     .0780438
> > .3334187
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > * Try to get separate estimates by sex
> > 
> > . bysort sex: binreg q7cat pre_post, rd cluster(id)
> > 
> > ______________________________________________________________
> > ______________
> > ___
> > -> sex = F
> > 
> > Iteration 1 : deviance =  570.9529
> > Iteration 2 : deviance =  570.9529
> > 
> > Residual df  =       423                                No. of obs =
> > 425
> > Pearson X2   =       425                                Deviance   =
> > 570.9529
> > Dispersion   =  1.004728                                Dispersion =
> > 1.349771
> > 
> > Bernoulli distribution, identity link
> > Risk difference coefficients
> >                                (standard errors adjusted for 
> > clustering on
> > id)
> > --------------------------------------------------------------
> > --------------
> > --
> >              |             Semi-Robust
> >        q7cat |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .2046461   .0391639     5.23   0.000     .1278862
> > .281406
> >        _cons |   .2057312   .0651479     3.16   0.002     .0780438
> > .3334187
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > ______________________________________________________________
> > ______________
> > ___
> > -> sex = M
> > 
> > Iteration 1 : deviance =  570.9529
> > Iteration 2 : deviance =  570.9529
> > 
> > Residual df  =       423                                No. of obs =
> > 425
> > Pearson X2   =       425                                Deviance   =
> > 570.9529
> > Dispersion   =  1.004728                                Dispersion =
> > 1.349771
> > 
> > Bernoulli distribution, identity link
> > Risk difference coefficients
> >                                (standard errors adjusted for 
> > clustering on
> > id)
> > --------------------------------------------------------------
> > --------------
> > --
> >              |             Semi-Robust
> >        q7cat |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .2046461   .0391639     5.23   0.000     .1278862
> > .281406
> >        _cons |   .2057312   .0651479     3.16   0.002     .0780438
> > .3334187
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > * Since that gave the same results as if I hadn't used
> > * -by- at all, try -if- instead
> > 
> > . binreg q7cat pre_post if sex=="M", rd cluster(id)
> > 
> > Iteration 1 : deviance =  290.7011
> > Iteration 2 : deviance =  290.7011
> > 
> > Residual df  =       213                                No. of obs =
> > 215
> > Pearson X2   =       215                                Deviance   =
> > 290.7011
> > Dispersion   =   1.00939                                Dispersion =
> > 1.364794
> > 
> > Bernoulli distribution, identity link
> > Risk difference coefficients
> >                                (standard errors adjusted for 
> > clustering on
> > id)
> > --------------------------------------------------------------
> > --------------
> > --
> >              |             Semi-Robust
> >        q7cat |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .1343025   .0536422     2.50   0.012     .0291657
> > .2394394
> >        _cons |   .3610246   .0910578     3.96   0.000     .1825546
> > .5394945
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > . binreg q7cat pre_post if sex=="F", rd cluster(id)
> > 
> > Iteration 1 : deviance =  273.5711
> > Iteration 2 : deviance =  273.5711
> > 
> > Residual df  =       208                                No. of obs =
> > 210
> > Pearson X2   =       210                                Deviance   =
> > 273.5711
> > Dispersion   =  1.009615                                Dispersion =
> > 1.315246
> > 
> > Bernoulli distribution, identity link
> > Risk difference coefficients
> >                                (standard errors adjusted for 
> > clustering on
> > id)
> > --------------------------------------------------------------
> > --------------
> > --
> >              |             Semi-Robust
> >        q7cat |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .2761905   .0566061     4.88   0.000     .1652445
> > .3871365
> >        _cons |    .047619   .0911676     0.52   0.601    -.1310661
> > .2263042
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > * Suppose I use -regress- instead of -binreg-. Then can I use -by-?
> > . by sex: regress q7cat pre_post, cluster(id)
> > 
> > ______________________________________________________________
> > ______________
> > ___
> > -> sex = F
> > 
> > Regression with robust standard errors                 Number of obs =
> > 210
> >                                                        F(  1,   104) =
> > 23.69
> >                                                        Prob > F      =
> > 0.0000
> >                                                        R-squared     =
> > 0.0767
> > Number of clusters (id) = 105                          Root MSE      =
> > .48134
> > 
> > --------------------------------------------------------------
> > --------------
> > --
> >              |               Robust
> >        q7cat |      Coef.   Std. Err.      t    P>|t|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .2761905   .0567421     4.87   0.000     .1636688
> > .3887121
> >        _cons |    .047619   .0913865     0.52   0.603    -.1336038
> > .2288419
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > ______________________________________________________________
> > ______________
> > ___
> > -> sex = M
> > 
> > Regression with robust standard errors                 Number of obs =
> > 215
> >                                                        F(  1,   108) =
> > 6.24
> >                                                        Prob > F      =
> > 0.0140
> >                                                        R-squared     =
> > 0.0183
> > Number of clusters (id) = 109                          Root MSE      =
> > .49378
> > 
> > --------------------------------------------------------------
> > --------------
> > --
> >              |               Robust
> >        q7cat |      Coef.   Std. Err.      t    P>|t|     [95% Conf.
> > Interval]
> > -------------+------------------------------------------------
> > --------------
> > --
> >     pre_post |   .1343025    .053768     2.50   0.014      .027725
> > .2408801
> >        _cons |   .3610246   .0912713     3.96   0.000     .1801091
> > .5419401
> > --------------------------------------------------------------
> > --------------
> > --
> > 
> > So in this case -regress- works with -by-, but -binreg- does 
> > not. I also
> > have sex as a numeric variable, but that doesn't alleviate 
> > the non-working
> > -by- (NPI). Any ideas?
> > 
> > Regards,
> > Lee
> > 
> > Lee Sieswerda, Epidemiologist
> > Thunder Bay District Health Unit
> > 999 Balmoral Street
> > Thunder Bay, Ontario
> > Canada  P7B 6E7
> > Tel: +1 (807) 625-5957
> > Fax: +1 (807) 623-2369
> > Lee.Sieswerda@tbdhu.com
> > www.tbdhu.com
> > 
> > *
> > *   For searches and help try:
> > *   http://www.stata.com/support/faqs/res/findit.html
> > *   http://www.stata.com/support/statalist/faq
> > *   http://www.ats.ucla.edu/stat/stata/
> > 
> *
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*
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