st: How to keep track on observations used in the model

["Supnithadnaporn, Anupit" <anupit.supnithad@gatech.edu>]

Dear Stata List Users,

When I run several logit models, Stata drops 176 observations with the warning
"varX != 0 predicts failure perfectly". I want to run the models using the same
set of observations.

How would I know which observations that Stata drops?
Does Stata have some command to track or keep the observations that used in the
last regression? 

Thank you,
Anupit


-- 
Anupit Supnithadnaporn
PhD Candidate
School of Public Policy
Georgia Institute of Technology
D.M.Smith Building TPAC Room 018
685 Cherry Street
Atlanta GA 30332


*
*   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/