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Re: st: RE: A modest proposal - missing data doesn't count


From   Austin Nichols <austinnichols@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: A modest proposal - missing data doesn't count
Date   Tue, 15 Jun 2010 12:40:46 -0400

Martin--
I agree.  In particular the treatment of p&q and p|q in the presence
of one missing value should worry anyone who actually uses data; this
is something that requires careful thought in any specific instance,
depending on what one is trying to estimate.

Allan--
Both x<10 and x>10 can be affected by presence of missings in x; think of
. gen dummy=(x<10)
for example.  No solution is perfect, and the treatment in functions
like max() and sum(), or egen functions like rowtotal() etc., logical
expressions, algebra on variables, and so forth may be hard for some
users to internalize, but so would another "solution" create
difficulties, not always immediately obvious, and bound to trip up
those of us who are used to the current behavior (but still get
tripped up by the current behavior when we aren't careful).

On Tue, Jun 15, 2010 at 6:53 AM, Martin Weiss <martin.weiss1@gmx.de> wrote:
<snip>
> I found the alternative approaches to missings presented in
> http://www.stata.com/meeting/uk08/KIMacD.presentation.ppt wholly
> unconvincing and worse than the current state.
<snip>
> -----Allan Reese-----
> It's so easy to forget that x<10 will not be affected by missing values
> but x>10 will be.  It would be good to have software that guards against
> pitfalls rather than invites you in.
<snip>

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