--- [email protected] wrote:
> when I use the following command:
> drop if x>450
> STATA drops a lot of observations, while when I exclude missing
> values as follows:
> drop if x>450 & x!=.
> STATA eliminates just a couple of observations
This is well known behaviour: In Stata missing values are the largest
possible values, so a missing value will be larger than 450. As result
if you type -drop if x>450- the missing values will also be dropped.
> I realized this when I run a regression including x as regressor. If
> STATA drops missing data with the first command, shouldn't drop the
> same observations when I run the regression after using the second
> command?
I don't think I understand the question. Do you think that -regress-
should influence the way -drop- behaves?
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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