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From |
"Joao Ricardo F. Lima" <[email protected]> |

To |
[email protected] |

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

Date |
Sun, 20 Apr 2008 03:23:46 -0300 |

Ramani, sorry but I can't help you. With me the selmlog works well. Send a mail to Rafa - [email protected]. Best, Joao Ricardo Lima 2008/4/20, Ramani Gunatilaka <[email protected]>: > 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/ > -- ------------------------------- 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/

**Follow-Ups**:**Re: st: losing observations while correcting for selection bias using selmlog***From:*"Ramani Gunatilaka" <[email protected]>

**References**:**st: losing observations while correcting for selection bias using selmlog***From:*"Ramani Gunatilaka" <[email protected]>

**Re: st: losing observations while correcting for selection bias using selmlog***From:*"Joao Ricardo F. Lima" <[email protected]>

**Re: st: losing observations while correcting for selection bias using selmlog***From:*"Ramani Gunatilaka" <[email protected]>

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