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RE: st: ice and random-number seed


From   "Medina, Tait Runnfeldt" <tmedina@indiana.edu>
To   "Rodrigo Alfaro A." <ralfaro@bcentral.cl>, "statalist@hsphsun2.harvard.edu"<statalist@hsphsun2.harvard.edu>
Subject   RE: st: ice and random-number seed
Date   Fri, 22 Aug 2008 14:34:36 -0400

Removing the weights does not seem to fix the problem.

However, I am able to work around the problem and obtain reproducible results by manually setting the seed both before -ice- and before -mim-. The -seed- option in -ice- does not need to be used. For example:

set seed 1234
ice var1 var2 var3 , m(2)
set seed 1234
mim: reg var1 var2 var3

Thank you for all of your suggestion.

Tait

-----Original Message-----
From: Rodrigo Alfaro A. [mailto:ralfaro@bcentral.cl]
Sent: Friday, August 22, 2008 10:16 AM
To: statalist@hsphsun2.harvard.edu
Cc: Medina, Tait Runnfeldt
Subject: RE: st: ice and random-number seed


///

Tait,

I think that your case is more complicated than Maarten's example.

(1) You are using weights. If I recall correctly ICE produces results
using iterations => order matters. My suggestion is to try your problem
without weights.

(2) Sorting could make some differences here. You could try imputing
one dataset each time using a specific seed. It is expected the
correlations between imputed variables (original y replication) should
be one.

Under (1) you have no solution. Under (2) you could control the problem
imputing 1 dataset at the time with specific seeds. We had problem (2)
with user-written routine hotdeck.

Rodrigo.

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