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RE: st: RE: the impute command


From   Richard Williams <Richard.A.Williams.5@nd.edu>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: RE: the impute command
Date   Wed, 19 May 2004 12:05:42 -0500

At 05:40 PM 5/19/2004 +0100, Nick Cox wrote:
. replace y = round(y)

is an alternative to -recode- here.
It works in the case of the example I gave, where -logit- is used. The -round- function could potentially be problematic if you were using the -impute- command, because you could conceivably have an imputed value of, say, 1.51, which would get rounded to two. A more all-purpose recode would be

recode y (min/.50 = 0)(.50/max = 1).


2. It is not at all clear that -impute-
is overall a very good way of doing it.
The manual makes the claim that impute "is often much better than deleting cases with any missing data." I agree that that statement is very debatable. Paul Allison in his book "Missing Data" makes a pretty good argument that listwise deletion is often better than some of the traditional alternatives that have been used, including the sort of thing done by impute. He also discusses more advanced techniques that can be better.


3. Various users have implemented some
better ways to do it.

4. Official Stata's support for good
ways of doing it is not that great, right
now. Information on what StataCorp will
add in the near future follows this colon:

(no, sorry, it's missing; impute your own
guess).
I agree. I'd like to see Stata implement some of the more powerful methods that are out there. I'd also like to see a portion of the Users Guide devoted to discussion of ways of handling missing data.

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Richard Williams, Notre Dame Dept of Sociology
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