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Re: st: dropped observations in bootstrap


From   Michael McCulloch <mm@pinest.org>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: dropped observations in bootstrap
Date   Sun, 7 Oct 2007 12:09:48 -0700

Brilliant! It makes perfect sense, that when the bootstrap is re-sampling it's attempting to generate variables that already exist. Thank you so much.


--- Maarten wrote:
 > One step you can take is to call the program -msm- you created,
 > outside -bootstrap- and see if it works, you can call it a second
 > time and you will see that it no longer works because several
 > variables are-generate-ed which already exist (where created during
 > the first call to -msm-). How did I know to call -msm- twice? I
 > made the same mistake you made many many times...
--- Michael McCulloch <mm@pinest.org> wrote:
 My temporary elation is tempered by the nagging discomfort of not
 knowing why the use of temporary variables resolved the issue. I'll
 proceed with your suggested -trace- approach. Many thanks, Michael
So, your program needs to create a number of variables. It leaves those
variables behind after it has finished. With -bootstrap- you run your
program multiple times (as many as you specify in the -reps()-
options). So now when you try to run the program multiple times, -msm-
tries to -generate- variables that already exist (were made by the
previous call to -msm-). This causes errors, as a result it returns no
results to -bootstrap- causing to display red X instead green dots.

Hope this helps,
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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