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   "Joao Ricardo F. Lima" <[email protected]>
To   [email protected]
Subject   Re: st: losing observations while correcting for selection bias using selmlog
Date   Sat, 19 Apr 2008 12:11:33 -0300

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 <[email protected]>:
> 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/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index