Date: Wed, 16 Feb 2005 22:37:50 -0500
Reply-To: Richard Ristow <wrristow@mindspring.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Richard Ristow <wrristow@mindspring.com>
Subject: Re: weighting
In-Reply-To: <000f01c51367$4d1ef1c0$7d04a8c0@beke.local>
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At 09:04 AM 2/15/2005, Antoon wrote:
>I have a question about weighting. I work with a file of young
>respondents that have committed minor delinquency. Half of the group
>got a learning and or work penalty, the other half (control group) got
>no (official) punishment.
>Regretfully the groups are not completely comparable as to ethnicity
>(6 categories) and whether the act was committed alone, or with others
>(4 categories). I would like to create weights to adjust for these
>differences.
That is, I take it, you want to assign weights such that, weighted,
this is a balanced design.
>I have two questions:
>1 Is my reasoning conceptually valid?
I think it's doubtful. There are better mathematical statisticians here
than I am (Marta? Hector? you there?), but my understanding is that you
do NOT try to correct an unbalanced design by weighting.
Weighting, when it goes beyond treating one observation as several when
it really represents several with the same observed values, is tricky,
and I don't pretend to understand the subtleties. The legitimate use, I
believe, is to match a stratified sample to the population
distribution.
You may want to post more about the analysis you intend: What dependent
variable or variables are you observing? Continuous, so this is an
ANOVA problem, or what?
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