|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
st: re: management of missing
<>
Rodrigo said
My question to the list is if Stata allows you to avoid dropping
observations based on the listwise criteria. I want to know this
because maybe this will be a possible solution for raising the sample
where the estimations are based.
No, for obvious reasons. Consider linear regression, where you
calculate X'X. Consider an X matrix, N x k, with some random elements
of each column missing. What does it mean to calculate sums of squares
and cross products of such a matrix? Calculating those sums over only
the feasible (pairwise) terms will not give you anything sensible
except in the limit, and even asymptotically, if the proportion of
missing data is fixed, driving N -> \infty probably won't help.
It sounds like you might be a good candidate for Stata's new manual on
Multiple Imputation.
Kit
Kit Baum | Boston College Economics and DIW Berlin | http://ideas.repec.org/e/pba1.html
An Introduction to Stata Programming | http://www.stata-press.com/books/isp.html
An Introduction to Modern Econometrics Using Stata | http://www.stata-press.com/books/imeus.html
*
* 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/