ERIC Number: EJ720454
Record Type: Journal
Publication Date: 2005-Mar
Pages: 25
Abstractor: Author
ISBN: N/A
ISSN: ISSN-0033-3123
EISSN: N/A
Available Date: N/A
Interpreting Degenerate Solutions in Unfolding by Use of the Vector Model and the Compensatory Distance Model
Van Deun, K.; Groenen, P. J. F.; Heiser, W. J.; Busing, F. M. T. A.; Delbeke, L.
Psychometrika, v70 n1 p45-69 Mar 2005
In this paper, we reconsider the merits of unfolding solutions based on loss functions involving a normalization on the variance per subject. In the literature, solutions based on Stress-2 are often diagnosed to be degenerate in the majority of cases. Here, the focus lies on two frequently occurring types of degeneracies. The first type typically locates some subject points far away from a compact cluster of the other points. In the second type of solution, the object points lie on a circle. In this paper, we argue that these degenerate solutions are well fitting and informative. To reveal the information, we introduce mixtures of plots based on the ideal point model of unfolding, the vector model, and on the signed distance model. In addition to a different representation, we provide a new iterative majorization algorithm to optimize the average squared correlation between the distances in the configuration and the transformed data per individual. It is shown that this approach is equivalent to minimizing Kruskal's Stress-2.
Springer, 233 Spring Street, New York, NY 10013. Tel: 212-460-1539; Fax: 212-460-1594.
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A
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