On Tue, 13 Aug 2013, Walter Anderson wrote:
> I have a set of survey data where I have answers to identify preference of
> three categories using three questions
>
> 1) a or b?
> 2) b or c?
> 3) a or c?
>
> and want to obtain weights for each of the preferences
>
> something like X(a) + Y(b) + Z(c) = 100%
You could use a Bradley-Terry model for paired comparisons. This estimates
a so-called "worth parameter" for each alternative/object (a, b, c)
and
these are typically scaled to sum to 1.
A wide collection of Bradley-Terry models including regressors is provided
in "BradleyTerry2", see http://www.jstatsoft.org/v48/i09/.
Basic Bradley-Terry models as well as other extended models for
preferences are provided in "prefmod", see
http://www.jstatsoft.org/v48/i10/.
Regression trees based on Bradley-Terry models are available in
"psychotree", see example("bttree", package =
"psychotree") and the
references on the corresponding manual page.
Finally, the "eba" package implements further extensions of the
Bradley-Terry model.
hth,
Z
> I am at a loss how how to calculate this from the data. Any help would be
> appreciated!
>
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