Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
st: st: Meaning of "." in Heckman Selection Models
From
"Clifton Chow" <[email protected]>
To
[email protected]
Subject
st: st: Meaning of "." in Heckman Selection Models
Date
Sat, 09 Jun 2012 12:51:45 -0500
I just ran a two-step Heckman selection model and a peculiar result came out on the explanatory variable of interest in the selection equation. Does someone know what a series of dots "." means in this context? How should it be interpreted and reported?
Here's the brief output from the results with X1 (a binary variable coded as 0 and 1) being my explanatory variable of interest.
Heckman logwage X1 X2 X3 if female==1, select (x1 X2 X3 X4 X5) twostep
LogWage Equation:
X1 | -.1290917 .0582952 -2.21 0.027 -.2433481 -.0148353
X2 | -.1528716 .0649873 -2.35 0.019 -.2802444 -.0254987
X3 | .1183843 .0684327 1.73 0.084 -.0157413 .2525098
Selection Equation:
select
X1 | 7.762731 . . . . .
X2 | .004973 .2220277 0.02 0.982 -.4301933 .4401393
X3 | .0188622 .238641 0.08 0.937 -.4488655 .4865898
X4 | .0196796 .1978019 0.10 0.921 -.368005 .4073641
X5 | -.0548543 .0817834 -0.67 0.502 -.2151467 .1054382
mills |
lambda | -.1344637 .0808789 -1.66 0.096 -.2929834 .0240561
-------------+----------------------------------------------------------------
rho | -0.38535
sigma | .34893481
lambda | -.13446366 .0808789
Thanks
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/