[Rasch] unfolding models and Rasch

David Andrich david.andrich at uwa.edu.au
Wed Aug 29 11:23:53 EST 2007

Donald. Yes, unfolding sounds right. The references which show the folding
of the Rasch model to the unfolding model are below:

Andrich, D. & Luo, G. (1993). A hyperbolic cosine latent trait model for
unfolding dichotomous single-stimulus responses. Applied Psychological
Measurement, 17 (3), 253-276.

Andrich, D. (1995). Hyperbolic cosine latent trait models for unfolding
direct-responses and pairwise preferences. Applied Psychological
Measurement, 19(3), 269-290.

Luo, G (1998)   A general formulation for unidimensionalunfolding and
pairwise preference models: Making explicit the latitude of acceptance.
Journal of Mathematical Psychology, 42,  400 - 417.

Luo, G. (2000) A joint maximum likelihood estimation procedure for the
hyperbolic cosine model of single-stimulus responses. Applied Psychological
Measurement, 24, 33-49.  

We have a program for analysing pairwise preference unfolding data.

All the best

David Andrich, BSc., MEd. (UWA), PhD (Chic), FASSA
Chapple Chair, Graduate School of Education 
The University of Western Australia
35 Stirling Highway
Crawley  6009
Telephone: +61 (0) 8 6488 1085 
Fax:          +61 (0) 8 6488 1052 
MBDP: M428 
Email: david.andrich at uwa.edu.au
On line Rasch measurement course July - November 2007
3rd International Conference in Rasch measurement, Perth, Australia

-----Original Message-----
From: rasch-bounces at acer.edu.au [mailto:rasch-bounces at acer.edu.au] On Behalf
Of Donald Bacon
Sent: Tuesday, 28 August 2007 9:25 PM
To: rasch at acer.edu.au
Subject: [Rasch] unfolding models and Rasch

Hi Raschers -

   I'm working with a scale wherein respondents read a scenario and then
rate how similar each of several statements are to their own way of thinking
about the scenario.  In this way we hope to locate where each respondent is
on a latent trait called reflective judgment, as well as calibrate each of
the statements.

   It occurs to me, however, that this is not like a common Rasch analysis.
For example, a respondent at a level 4 on a 7 level latent trait will rate
both a level 1 statement and a level 7 statement as being highly dissimilar
to his or her way of thinking.  Thus, response probabilities do not increase
monotonically with respondent ability.  Would some type of unfolding model
work better?  Or is there some way to model this in Rasch?


Thanks for any insight you might have -


Don Bacon

Associate Professor of Marketing

Daniels College of Business
University of Denver
dbacon at du.edu, 303-871-2707
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