Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: losing observations while correcting for selection bias using selmlog


From   "Ramani Gunatilaka" <ramani.gunatilaka@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: losing observations while correcting for selection bias using selmlog
Date   Sun, 20 Apr 2008 12:32:16 +0600

Thanks Joao, will do that. In the meanwhile, here's hoping I get a few
more responses. :(
Best,
Ramani


On 20/04/2008, Joao Ricardo F. Lima <jricardofl@gmail.com> wrote:
> Ramani,
>
> sorry but I can't help you. With me the selmlog works well. Send a
> mail to Rafa - rdehoyos@worldbank.org.
>
> Best,
>
> Joao Ricardo Lima
>
>
>
> 2008/4/20, Ramani Gunatilaka <ramani.gunatilaka@gmail.com>:
> > Dear Joao Lima,
> > Thank you for your response. Sample size by select_m depvar category
> > is as follows, there are no missing values:
> > tabulate selmcat
> >
> > categorical
> > variable
> > showing
> > employment
> > sector
> > choice       Freq.      Percent Cum.
> >
> > 1       1,884   6.36    6.36
> > 2      12,238   41.34   47.70
> > 3       3,723   12.58   60.28
> > 4       5,043   17.03   77.31
> > 5       6,716   22.69   100.00
> >
> > Total      29,604       100.00
> >
> > . sum w3
> >
> > Variable        Obs     Mean    Std. Dev.       Min     Max
> >
> > w3       3723   4.013316        1.095727        -6.050407       6.69982
> >
> > Public sector wage variable W3 has values for all 3723 public employee
> > observations and missing values for the observations relating to other
> > employment categories.
> >
> > . sum $basefactors1
> >
> > Variable        Obs     Mean    Std. Dev.       Min     Max
> >
> > male      29604 .6367721        .4809379        0       1
> > age      29604  38.82702        13.52627        11      93
> > agesqd      29604       1690.491        1133.976        121     8649
> > SL_Tamil      29604     .042832 .2024817        0       1
> > I_Tamil      29604      .056614 .2311074        0       1
> >
> > Moor      29604 .0472571        .2121919        0       1
> > other      29604        .0040873        .0638022        0       1
> > jsecondary      29604   .2399676        .4270706        0       1
> > ssecondary      29604   .5070599        .4999586        0       1
> > tertiary      29604     .0330699        .178822 0       1
> >
> > managerial      29604   .0839751        .2773552        0       1
> > professional      29604.0482029 .2141984        0       1
> > technician      29604   .0463789        .2103078        0       1
> > clerical      29604     .0352317        .1843681        0       1
> > service      29604      .0671869        .2503496        0       1
> >
> > agricultural      29604 .2110526        .4080625        0       1
> > elementary      29604   .2822929        .4501227        0       1
> > manuf      29604        .2341913        .4234995        0       1
> > services      29604     .3759627        .4843786        0       1
> > rural      29604        .8120524        .3906769        0       1
> >
> > estates      29604      .0733685        .2607448        0       1
> > CP      29604   .1397784        .3467628        0       1
> > SP      29604   .1732874        .3785019        0       1
> > NWP      29604  .1327523        .3393126        0       1
> > NCP      29604  .0744494        .2625053        0       1
> >
> > Uva      29604  .0816444        .2738268        0       1
> > Sab      29604  .118261 .3229224        0       1
> >
> > I don't have any missing values for $basefactors1 variables - almost
> > all are 0/1 dummies.
> >
> > . sum $selfactors
> >
> > Variable        Obs     Mean    Std. Dev.       Min     Max
> >
> > nempld  29604   2.234901        1.141517        0       9
> > nempld_m        29604   5.670382        5.652145        0       54
> > children        29604   .6210985        .8557174        0       6
> > mother  29604   .140758 .3477776        0       1
> > hh_head 29604   .4264626        .494571 0       1
> >
> > married 29604   .6940616        .4608115        0       1
> > malemarried     29604   .4621673        .4985751        0       1
> >
> > There are no missing values for the demographic variables used for the
> > selection equation.
> >
> > Thank you for your help.
> > Best,
> > Ramani
> >
> >
> > On 19/04/2008, Joao Ricardo F. Lima <jricardofl@gmail.com> wrote:
> > > Ramani,
> > >
> > > please give us more information. How many observations do you have?
> > > Are there missing values to the independent variables? Could you send
> > >
> > > sum w3 $basefactors1 selmcat $selfactors
> > >
> > > I used selmlog and with missing values, the program drop that observations.
> > >
> > > Best,
> > >
> > > Joao Lima
> > >
> > > 2008/4/19, Ramani Gunatilaka <ramani.gunatilaka@gmail.com>:
> > > > Dear Statalist,
> > > > I am using selmlog to estimate wage functions. The full sample is of
> > > > labour market participants.
> > > > For the multinomial logit part, I have five categories - 1.
> > > > unemployed, 2. contributing family workers, own account workers,
> > > > employers, 3. public employees 4. private formal employees 5. informal
> > > > employees.
> > > > I have wage data only for categories 3, 4 and 5. I want to estimate
> > > > wage functions for each of these. As suggested by Rafa de Hoyes in an
> > > > old Statapost (12 April 2006), I defined separate wage variables for
> > > > each of these wage categories.
> > > > w3 is the wage data for public employees. There are 3723 of them.
> > > >
> > > > Now when I run the following model for the public sector, the eventual
> > > > wage equation ends up with only about 400 observations.
> > > >
> > > > selmlog w3 $basefactors1, select(selmcat=$basefactors1 $selfactors) showmlogit
> > > >
> > > > Can somebody please tell me why this is so?
> > > > BTW, I intend bootstrapping to fix the standard errors but will embark
> > > > on that time-consuming exercise once I sort out this problem.
> > > > Thank you in advance,
> > > > Ramani
> > > > *
> > > > *   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/
> > > >
> > >
> > >
> > > --
> > > -------------------------------
> > > Joao Ricardo Lima
> > > Professor
> > > UFPB-CCA-DCFS
> > > +553138923914
> > > -------------------------------
> > > *
> > > *   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/
> > >
> > *
> > *   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/
> >
>
>
> --
> -------------------------------
> Joao Ricardo Lima
> Professor
> UFPB-CCA-DCFS
> +553138923914
> -------------------------------
> *
> *   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/
>
*
*   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/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index