st: use of rologit

["Data Analytics Corp." <dataanalytics@earthlink.net>]

Hi,

A potential client asked for a form of analysis sometimes done in market 
research called maximum-difference (maxdiff) analysis.  Basically, 
consumers are presented with a series of product attributes (say, four 
at a time or a "quad") and then are asked to select the one they prefer 
the most and the one they prefer the least.  For a quad, the other two 
non-selected attributes just fall in the middle.  This is repeated 
several times with the attributes rotating following an experimental 
design.  Since the attributes are rated, I was thinking of using rologit 
to estimate a model.  But then I found a statement in the reference 
manual that says that "rologit does not allow for other forms of 
incompleteness, for instance, data in which respondents indicate which 
of four cars they like best, and which one they like least, but not how 
they rank the two intermediate cars."  But this is exactly my problem.  
Does anyone know how to trick rologit, or know of an ado file to handle 
this problem?

Thanks,

Walt



--
________________________

Walter R. Paczkowski, Ph.D.
Data Analytics Corp.
44 Hamilton Lane
Plainsboro, NJ 08536
________________________
(V) 609-936-8999
(F) 609-936-3733
dataanalytics@earthlink.net
www.dataanalyticscorp.com

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/