A comparison of methods for determining dimensionality in Rasch measurement

Smith, Rachel

doi:10.1080/10705519609540027

Cited by 126 publications

(101 citation statements)

References 5 publications

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“…DIF is a breach of the assumptions of unidimensionality, 20 but it has also been argued that DIF can be evaluated only if the conditions for fit to the Rasch model have been satisfied. 29 As it is possible to have data which fit the model, but which also display DIF, we have adopted a pragmatic approach whereby we have considered DIF as one possible contribution to misfit, and thus deliberately refitted data to the model after adjustment for DIF.…”

Section: Discussionmentioning

confidence: 99%

Cross-cultural validity of FIM in spinal cord injury

et al. 2006

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Objective: To analyse cross-culture validity of the Functional Independence Measure (FIMt) in patients with a spinal cord injury using a modern psychometric approach. Settings: A total of 19 rehabilitation facilities from four countries in Europe. Participants: A total of 647 patients at admission, median age 46 years, 69% male. Methods: Data from the FIMt, collected on inpatient admission, was fitted to the Rasch model. A detailed analysis of scoring functions of the seven categories of the FIMt items was undertaken before to testing fit to the model. Categories were rescored where necessary. Fit to the model was assessed initially within country, and then in the pooled data. Analysis of differential item functioning (DIF) was undertaken in the pooled data for each of the FIMt motor and social cognitive scales, respectively. Final fit to the model was tested for breach of local independence by principle components analysis (PCA). Results: The present scoring system for the FIMt motor and cognitive scales, that is a seven category scale, was found to be invalid, necessitating extensive rescoring. Following this, DIF was found in a number of items within the motor scale, requiring a complex solution of splitting items by country to allow for the valid pooling of data. Five country-specific items could not be retained within this solution. The FIM cognitive scale fitted the Rasch model after rescoring, but there was a substantial ceiling effect. Conclusions: Data from the FIMt motor scale for patients with spinal cord injury should not be pooled in its raw form, or compared from country to country. Only after fit to the Rasch model and necessary adjustments could such a comparison be made, but with a loss of clinical important items. The FIM cognitive scale works well following rescoring, and data may be pooled, but many patients were at the maximum score.

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Section: Discussionmentioning

confidence: 99%

Cross-cultural validity of FIM in spinal cord injury

et al. 2006

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“…The simplest of the IRT models is the Rasch model. A series of studies have been conducted to investigate the differences between Rasch and exploratory factor analysis (Chang, 1996;Green, 1996;Smith, 1996;Wright, 1996). Some of the problems that factor analytic procedures pose under CTT can be averted with the use of the Rasch model under IRT as shown in those studies.…”

Section: The Rasch Measurement Modelmentioning

confidence: 99%

“…According to a simulation study (Smith, 1996), eigenvalues greater than 1.40 did not occur for the second factor in simulated unidimensional dichotomous and rating-scale data that were generated based on the RSM. The second eigenvalues fell mostly within the 1.20 to 1.30 range.…”

Section: Principal Component Analysis (Pca)mentioning

confidence: 99%

Rasch Rating Scale Modeling of Data From the Standardized Letter of Recommendation

Kim

Kyllonen

2006

ETS Research Report Series

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The Standardized Letter of Recommendation (SLR), a 28-item form, was created by ETS to supplement the qualitative rating of graduate school applicants' nonacademic qualities with a quantitative approach. The purpose of this study was to evaluate the following psychometric properties of the SLR using the Rasch rating-scale model: dimensionality, reliability, item quality, and rating category effectiveness. Principal component and factor analyses were also conducted to examine the dimensionality of the SLR. Results revealed (a) two secondary factors underlay the data, along with a strong higher order factor, (b) item and person separation reliabilities were high, (c) noncognitive items tended to elicit higher endorsements than did cognitive items, and (d) a 5-point Likert scale functioned effectively. The psychometric properties of the SLR support the use of a composite score when reporting SLR scores and the utility of the SLR in higher education and in admissions.

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“…For the time facet, infit ranges from 0.98 to 1.02; for the participants facet, infit values range from 0.94 to 1.05, and for the items facet, infit values range from 0.95 to 1.08, largely within the acceptable range. According to Smith (1996Smith ( , 2002, we can interpret this result as evidence of unidimensionality of the latent trait. Because previous studies have shown that positive and negative formulations of items sometimes load on different dimensions, we deemed it important to provide further evidence of unidimensionality.…”

Section: Methodsmentioning

confidence: 99%

The many-facet Rasch model in the analysis of the go/no-go association task

Vianello

Robusto

2010

Behavior Research Methods

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This article provides a many-facet Rasch measurement (MFRM) analysis of go/no-go association task (GNAT)-based measures of implicit attitudes toward sweet and salty food. We describe the statistical model and the strategy we adopted to score the GNAT, and we emphasize that, when analyzing implicit measures, MFRM indexes have to be interpreted in a peculiar way. In comparison with traditional scoring algorithms, an MFRM analysis of implicit measures provides some additional information and suffers from fewer limitations and assumptions. MFRM might help to overcome some limitations of current implicit measures, since it directly addresses some known issues and potential confounds, such as those related to a rational zero point, to the arbitrariness of the metric, and to participants' task-set switching ability.

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A comparison of methods for determining dimensionality in Rasch measurement

Cited by 126 publications

References 5 publications

Cross-cultural validity of FIM in spinal cord injury

Cross-cultural validity of FIM in spinal cord injury

Rasch Rating Scale Modeling of Data From the Standardized Letter of Recommendation

The many-facet Rasch model in the analysis of the go/no-go association task

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