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 <[email protected]> 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 <[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/
>
*
* 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/
