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ERIC Number: ED309199
Record Type: Non-Journal
Publication Date: 1989-Apr
Pages: 35
Abstractor: N/A
Reference Count: N/A
ISBN: N/A
ISSN: N/A
Stepwise Item Selection Procedures for Rasch Scales Using Quasi-Loglinear Models. Project Psychometric Aspects of Item Banking No. 44. Research Report 89-3.
Knol, Dirk L.
Two iterative procedures for constructing Rasch scales are presented. A log-likelihood ratio test based on a quasi-loglinear formulation of the Rasch model is given by which one item at a time can be deleted from or added to an initial item set. In the so-called "top-down" algorithm, items are stepwise deleted from a relatively large initial item set, whereas in the "bottom-up" algorithm items are stepwise added to a relatively small initial item set. Both algorithms are evaluated through a simulation study with generated data. Item parameters are given for four generated unidimensional data sets and two generated two-dimensional sets. Abilities were randomly sampled from a multivariate normal distribution with a sample size of 1,000. Results for the top-down algorithm were poor, but results for the bottom-up algorithm were more encouraging. It is suggested that alternating the bottom-up algorithm with one or two iterations of the top-down algorithm would allow the procedure to reject items that were added incorrectly in a previous step. Eight tables illustrate the item parameters and the use of both algorithms for the generated data. (SLD)
Bibliotheek, Department of Education, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Publication Type: Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: Twente Univ., Enschede (Netherlands). Dept. of Education.