• The Pure and Applied Mathematics
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• v.20 no.1
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• pp.59-70
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• 2013

The purpose of this study was to develop a zero-inflated Rasch (ZI-Rasch) model, a combination of the Rasch model and the ZIP model. The ZI-Rasch model was considered in this study as an appropriate alternative to the Rasch model for zero-inflated data. To investigate the relative appropriateness of the ZI-Rasch model, several analyses were conducted using PROC NLMIXED procedures in SAS under various simulation conditions. Sets of criteria for model evaluations (-2LL, AIC, AICC, and BIC) and parameter estimations (RMSE, and $r$) from the ZI-Rasch model were compared with those from the Rasch model. In the data-model fit indices, regardless of the simulation conditions, the ZI-Rasch model produced better fit statistics than did the Rasch model, even when the response data were generated from the Rasch model. In terms of item parameter ${\lambda}$ estimations, the ZI-Rasch model produced estimates similar to those of the Rasch model.

• Korean Journal of Social Welfare
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• v.59 no.4
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• pp.273-296
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• 2007

In this Study, to reconstruct the disability identity scale(Lee and Shin, 2006)), Rasch rating scale model was applied to the four sub-dimensions of the Disability Identity Scale in a sample of spinal cord injuries(N=397). The Disability Identity Scale was verified by explorative factor analysis and confirmatory factor analysis. However, factor analytic procedures can't evaluate item-fit indices, item difficulty, and appropriate scale category. A number of limitations posed by confirmatory factor analytic procedures can be averted with the use of Rasch rating scale model which is in the item response theory(IRT). So in this study, Rasch model was applied to the Disability Identity Scale. Results revealed that (A) 20 items were selected from Rasch model, (B) the difficulty level of the Disability Identity Scale was the average level, (C) 4-point rating scale was appropriate for the Disability Identity Scale. Finally, we could suggest that the sub-dimensions concepts of the disability identity became clearer and items were to the good fitting.

• Physical Therapy Korea
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• v.21 no.2
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• pp.74-81
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• 2014

The versions of the Oswestry disability questionnaire (ODQ) is regarded as one of the most extensively used condition-specific instruments measuring disability resulting from low back pain. It has been shown to have adequate psychometrics, reliability, validity, and responsiveness as a whole, yet the summated total score of the instrument often provide little information to rehabilitation clinicians. A keyform analysis based on Rasch measurement model is an innovative way of illustrating the specific test items that an individual may or may not perform. By applying the keyform of the Rasch measurement model to the ODQ, rehabilitation clinicians may able to select more challenging ODQ items matching an individual's ability and document them as attainable treatment goals. The results demonstrated how a keyform analysis assist to setting possible goals for the treatment of individuals with low back pain. Forty-two individuals with low back pain were recruited from rehabilitation clinics in Gainesville, Florida. A series of Rasch analyses on the 10 items of the ODQ were performed using Winsteps software. The performance of two individuals on those 10 items was illustrated on the keyform. The keyform analysis of the Rasch measurement model may be translated into a useful tool for making clinical judgements.

• Physical Therapy Korea
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• v.11 no.2
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• pp.9-16
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• 2004

The purpose of this study was to validate the Korean version of the Gross Motor Function Measure (GMFM) using Rasch analysis. The data was obtained from the assessments of 59 children with cerebral palsy in Korea and were applied to Rasch's rating scale model to estimate the difficulty and goodness-of-fit of each item. Rasch modeling helped us to identify 76 items from the original 88-item GMFM that form an unidimensional hierarchical scale to rearrange 76 items in order of difficulty. Reliability coefficients of the 88-item and 76-item GMFM were .99 and .99, respectively. In this preliminary report, the Korean version of GMFM seems to have significant validity and reliability. These results may be useful in assessment of gross motor functions in children with cerebral palsy.

• The Mathematical Education
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• v.55 no.1
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• pp.1-19
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• 2016

Given the importance of understanding the equal sign in developing early algebraic thinking, this paper investigated how a total of 695 students in grades 2~6 understood the equal sign. The students completed a questionnaire with three types of items (equation structure, equal sign definition, and open equation solving) based on the construct map by four different levels of understanding the equal sign. The questionnaire was analyzed by Rasch model. The results showed that about 80% of the students were at least Level 3 which means a basic relational understanding of the equal sign. However, the success rates varied across grades and it was noticeable that about 70% of the second graders remained at Level 1 or 2 which maintains an operational understanding of the equal sign. The results of item types demonstrated that item difficulty for the advanced relational thinking was the highest and this is the same even for the Level 4 students. This paper is expected to investigate elementary school students' understanding of the equal sign and provide implications of how to deal with the equal sign in the elementary school.

• 재활복지
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• v.20 no.4
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• pp.135-156
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• 2016

The purpose of this study was to investigate item goodness-of-fit of Childhood Autism Rating Scale(CARS), Rasch rating scale model was applied to 15 items of the CARS in a sample of pervasive development disorder(n=238). An assumption to test Rasch Model, which is satisfaction of unidimensionality, is regarded through PCAR analysis, and jMetrik 4.03 program is used to test the goodness-of-fit of items. The results of this study were: First, 5-point rating scale was appropriate for the CARS rather than 7-point original rating scale. Second, the result of examining the CARS questions goodness-of-fit, there was a overfitting or misfitting items according to the classified groups. Only in particular Q11 item in diagnosis subject of integration population of autism has become inappropriate. Therefore, it is necessary to provide education for the CARS more systematically. Thirdly, the result of comparing the personal attributes score and difficulty of a CARS question, Q2, Q3, Q10, Q11 items are necessary to distinguish conceptually defined in more detail. Fourth, the results of investigating the difficulty of CARS question, it was found to exhibit a verbal communication is most serious problem for the population of autism.

• Physical Therapy Korea
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• v.24 no.4
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• pp.20-28
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• 2017

Background: Rasch analysis has the advantage of placing both the items and the person along a single ratio scale and calibrates person ability and item difficulty onto an interval scale by logits. Therefore, Rasch analysis has been recommended as a better method for evaluating functional outcome questionnaires than traditional analyses. Objects: The aim of current study was to investigate item fit, item difficulty, rating scale, and separation index of the Korean version of the Fullerton Advanced Balance (KFAB) scale using Rasch analysis. Methods: In total, 93 patients with stroke (male=58, female=35) participated in this study. To investigate the item fit, difficulty, rating scale, and separation index of the KFAB scale, Rasch analysis was completed by the Winsteps software program. Results: In this study, all items of the KFAB scale were included in the Rasch model. The most difficult item was 'standing with feet together and eyes closed', and the easiest item was 'two-footed jump'. The rating scale was a 4-point scale instead of the original 5-point scale. Person and item separation indices showed high values that can identify a person with a wide range of balance ability. Conclusion: The KFAB scale appears to be a reliable and valid tool to assess balance function in patients with stroke. Furthermore, the scale was found to discriminate among stroke patients of varying balance abilities.

• Physical Therapy Korea
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• v.15 no.3
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• pp.26-34
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• 2008

The purposes of this study were to assess and modify the original classification categories of the modified Oswestry Low Back Pain Disability Questionnaire (ODQ) and to determine the unidimensionality of the modified ODQ applying Rasch Analysis. The data were obtained from 108 work-related low back pain patients by physical therapists. Construct validity of the scale using the Rasch model required the structure of the rating scale to be modified from 6 response levels to 4 response levels. Eight items from the modified ODQ fit the Rasch model. The items, "pain intensity" and "social life" showed misfit statistics. In general, the order of item difficulty of the remaining 8 items showed a logical item difficulty hierarchy with the "changing degree of pain" item being the most difficult and the "walk" item being the easiest. The results showed that further study is needed to expand the construct of ODQ including additional higher-level items related to work activities. This study may be useful for establishing a standard method to assess the functionality of low back pain patients.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.567-578
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• 2014

PEAS (performance enhancement attitude scale) has been used to measure attitude and disposition toward doping in elite athlete. It is constructed of 17-item, 6-point scale. The purpose of this study was to verify validity of the PEAS for Korean elite player through Rasch model. The scale was administered to 438 Korean elite players. Principal component analysis was used to verify unidimensionality using SPSS program. Rasch measurement computer program, WISTEPS, was used to estimate goodness-of-fit of items and category structure. Differenctial item functioning by gender was also estimated by the WINSTEPS program. All alpha level was set at 0.05. First, principal component analysis showed that unidimensionality is satisfied as over 20.0% of variance of eigenvalue. Second, category probabilities curve showed 5-point scale was better than 6-point scaled statistically. Third, seven items (1, 9, 10, 12, 13, 14, 17) in the 17-item were not good model fit and three items (3, 12, 13) were estimated as the differential item functioning. This study showed that 9-item, 5-point scale is better PEAS to Korean elite player.

• The Journal of Korean Medicine
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• v.43 no.2
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• pp.27-41
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• 2022

Objectives: There should be an objective analysis on the academic competency for incorporating Computer-based Test (CBT) in the education of traditional Korean medicine (TKM). However, the Item Response Theory (IRT) for analyzing latent competency has not been introduced for its difficulty in calculation, interpretation and utilization. Methods: The current study analyzed responses of 390 students of 8 years to the herbology test with 14 items by utilizing Rasch model, and the characteristics of test and items were evaluated by using characteristic curve, information curve, difficulty, academic competency, and test score. The academic competency of the students across gender and years were presented with scale characteristic curve, Kernel density map, and Wright map, and examined based on T-test and ANOVA. Results: The estimated item, test, and ability parameters based on Rasch model provided reliable information on academic competency, and organized insights on students, test and items not available with test score calculated by the summation of item scores. The test showed acceptable validity for analyzing academic competency, but some of items revealed difficulty parameters to be modified with Wright map. The gender difference was not distinctive, however the differences between test years were obvious with Kernel density map. Conclusion: The current study analyzed the responses in the herbology test for measuring academic competency in the education of TKM using Rasch model, and structured analysis for competency-based Teaching in the e-learning era was suggested. It would provide the foundation for the learning analytics essential for self-directed learning and competency adaptive learning in TKM.