• Physical Therapy Korea
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• v.14 no.1
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• pp.82-89
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• 2007

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a valid and widely used instrument for the assessment of osteoarthritis patients. In this study, data was obtained from the out-patients with painful osteoarthritis of the knee. One hundred-three out-patients were interviewed by physical therapists. In an exploratory way, a Korean version of the KWOMAC was analyzed for unidimensionality, item separation, and item difficulty using the Winsteps programs. Ninety-five patients with osteoarthritis of the knee over 65 years were analyzed for Rash analysis. In the analysis several functional items poorly fit to the model. These items included "heavy domestic duties" and "standing". In the pain domain, one item ("at night while in bed") did not fit the model. In the stiffness domain one item ("after sitting, lying, or resting later in the day") did not fit the model. Although 4 items from the 3 domains (pain, stiffness, function domain) do not fit well, the KWOMAC domains were confirmed by Rasch analysis. Thus the KWOMAC needs to be further examined before it can be used to properly determine the health status of the elderly with OA.

• Physical Therapy Korea
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• v.21 no.4
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• pp.56-66
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• 2014

For maintaining adequate psychometric properties when reducing the number of items from an instrument, item level psychometrics is crucial. Strategies such as low item correlation or factor loadings, using classical test theory, have traditionally been advocated. The purpose of this study is to describe the development of a new short form assessing the impact of low back pain on physical activity. Rasch measurement model has been applied to the International Classification of Functioning, Disability and Health Activity Measure (ICF-AM). One hundred and one individuals with low back pain aged 19-89 years (mean age: $48.1{\pm}17.3$) who live in the community were participated in the study. Twenty-seven items of lifting/carrying construct of the ICF-AM were analyzed. Ten items were selected from the construct to create a short form. Item elimination criteria include: 1) high or low mean square (out of the range: .6-1.4 for the fit statistics), 2) similar item calibrations to adjacent items, 3) person separation value, and item-person map for potential gap in person ability continuum. All 10 items of the short form fit to the Rasch model except one item (i.e., carrying toddler on back). Despite its high infit and outfit statistics (1.90/2.17), the item had to be reinstated due to potential gaps at the upper extreme of person ability level. The short form had a slightly better spread of person ability continuum compared to the entire set of item. The created short form separated individuals with low back pain into nearly 4 groups, while the entire set of items separated the individuals into 6 groups. The findings prompted multidimensional models for better explanation of the lifting/carrying domain. The item level psychometrics based on the Rasch model can be useful in developing short forms with rationally retained items.

• 재활복지
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• v.21 no.2
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• pp.169-190
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• 2017

The purpose of this study was to investigate item goodness-of-fit of Scale, Rasch rating scale model was applied to 5 dimensions 24 items of the Test of Performance Strategies (TOPS) in a sample of athletes with physical disabilities (n=215). An assumption to test Rasch Model, which is satisfaction of unidimensionality, is regarded through PCAR test, and WINSTEPS 3.65 program is used to test the goodness-of-fit of items. The results of this study were: First, 3-point rating category was appropriate for the TOPS instead of the existing 5-point rating category. Second, as a result of analyzing the goodness-of-fit of the items, 21 items of the TOPS were suitable, but 3 items were not. Third, the item reliability of person separation of the TOPS was acceptable, but the person reliability of item separation was not suitable and it was necessary to adjust the item order considering the difficulty level of the items. Fourth, as a result of comparing the individual attribute score and the difficulty level through the Item-Person Map, the distribution of the item difficulty distribution was shown to be biased in some factors compared to the personal attribute score distribution.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.482-486
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• 2006

1990년대 말부터 전세계적으로 이동통신 사용자의 수는 급증하였고, 2000년대에 들어서면서부터는 모바일 인터넷 사용자 수도 점차적으로 증가하고 있는 추세이다. 그러나 오프라인이나 기존e-commerce에서의 서비스 품질 측정에 대한 연구는 활발하게 이루어진 반면, 모바일 상거래에 관한 연구는 미미한 실정이다. 본 연구는 모바일 상거래에 대한 고객만족도에 영향을 미치는 요인을 찾아내고자 하는데 그 목적이 있다. 이를 위해, 모바일 상거래의 특징을 살펴봄으로써 모바일 상거래에서 고객 만족도에 영향을 미치는 요인들을 추출하고 체계적인 프레임워크를 제시하고자 한다. 또한 본 연구에서는 모바일 상거래 중 디지털 컨텐츠 다운로드 서비스의 실사용자들을 대상으로 설문조사를 실시하였으며 이를 토대로 Rasch 모형을 적용하여 고객군을 분류하고 요인별 중요도를 파악하며 고객만족에 대한 확률적 예측을 실행하였다.

• Physical Therapy Korea
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• v.23 no.4
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• pp.71-80
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• 2016

Background: Functional capacity evaluations (FCEs) are designed to systematically assess the capacity to perform work-related tasks and to determine worker's ability to return to the previous job following work-related injuries. These evaluations may be rated either by clinician or worker. There has been a lack of consensus between the two scoring methods. Objects: This study aimed: 1) to confirm if the data are fit to the Rasch rating scale model and 2) to investigate the item-level concordance rate between the ratings of clinician and injured worker of the FCE. Methods: A cross-sectional study was conducted with a sample (n=124) of a rehabilitation program with the Occupational Rehabilitation Data Base for workers with low back pain. The functional capacity evaluation at admission and discharge was administered to clinicians and workers. The data were analyzed using both classical test theory-based Pearson's r and intra-class coefficient followed by item-level analysis with Rasch rating scale model. Results: All items of the FCE, except sitting items rated by clinician at admission and handling items rated by both clinician and worker throughout admission and discharge, were acceptable fit statistics with minor out of ranges for a misfit criterion. This may indicate that the items of the FCE overall fit to the Rasch rating scale model. Few problematic items responding differently to clinician and worker both at admission and discharge were detected with the differential item functioning analysis despite the excellent concordance rate using the two conventional statistics-sitting and handling items at admission and handling item at discharge. Conclusion: The item-level speculations using Rasch analysis of the FCE demonstrate that the ratings of clinician and self ratings of worker were psychometrically acceptable though there was an apparent discrepancy between the raters both at admission and discharge.

• Physical Therapy Korea
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• v.22 no.3
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• pp.61-70
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• 2015

To develop an effective and efficient measurement system for tracking changes of functional status across two measures, it is essential to integrate information and communicate scores across two measures. The lack of communication between two measures leads to score incompatibility. A potential solution would be the development of a crosswalk table between those measures. Prior to creating a crosswalk table, selecting common items between two measures is critical. By using the Oswestry low back pain disability questionnaire (Oswestry) and a short form measuring disability resulting from low back pain, item level statistics as well as differential item functioning (DIF) using the Rasch measurement were investigated. Eighty-two participants with known group validity were recruited. Based on the application of the Rasch measurement model, item difficulties across the two measures were logically and hierarchically ordered. Ceiling effects for both measures were detected, which were not be able to be effectively measured with the two measures. The DIF analysis across the two measures confirmed that five paired items were found to have DIF and five common items were selected for common items. Although five paired items function differently across the Oswestry and the short form, all items of both measures were well targeted study participants. The common items selected by the Rasch measurement model may be effective when creating a crosswalk table between the Oswestry and the short form.

• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.1-8
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• 2009

Purpose: The purpose of this study was to examine the functional category, the item structure and the model-data fit of the neck disability index (NDI) of neck pain subjects by performing a Rasch rating scale analysis. Methods: The data was obtained from the assessments of 71 college students (males: 27, females: 44) with neck pain. The data of the NDI was applied to the Rasch's rating scale model to estimate the difficulty of items, the goodness-of-fit of each item, the separation reliability and index, and the rating scale. Results: The 'sleep' item showed misfit and nine items were founds to be fits for self-reporting of disability due to neck pain. The most difficult item of the remaining 9 items was 'work' and the easiest item was 'headache'. The transformation formula score=(logit score+7.10)/(7.10+0.11)$\times$100. The 6 response levels of the NDI were validated according to the structure of the rating scale. The item and subject reliability of the separation reliability was 0.97 and 0.85, respectively. Conclusion: We proved that the NDI for self-reporting of disability of daily activities due to mild neck pain was valid and reliable. This study suggests that individuals with mild neck pain may be assessed by using the modified NDI that does not include the 'sleep' item in the 10 items of NDI.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.1-18
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• 2021

The purpose of the study was to examine the psychometric properties of the personal teaching efficacy of the Mathematics Teaching Efficacy Beliefs Instrument and revise the scale for the use of Korean elementary school teachers. Data were collected from 299 elementary teachers. A Rasch analysis was used to evaluate unidimensionality and appropriateness of category use and item difficulty levels. Moreover, person separation and reliability as well as item separation and reliability were examined using the revised scale. Results suggested that the original personal teaching efficacy scale (13 items with five categories) had several problems in its psychometric properties. Thus, we revised the scale into eight items with four categories. The follow-up analysis results showed the revised scale provided sufficient psychometric properties for measuring Korean elementary school teachers' self-efficacy beliefs for teaching mathematics. Limitations and implications of the study were also discussed.

• 한국체육학회지인문사회과학편
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• v.58 no.1
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• pp.295-308
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• 2019

The purpose of the present study is to apply a health belief model to the serious perception of an increase in youth obesity, and to develop and validate a measurement tool for youth obesity prevention among this group who are experiencing increasing rates of obesity. The specific goals of this study are to 1) apply a health belief model to develop a measurement tool for obesity prevention among youth who are seeing rising rates of obesity, and 2) provide an integrated validation procedure and foundation for developing this measurement tool. A total of 1801 high school students[sample1: 902(male:464,female:438); sample2: 899(male:464,female:438)] were recruited and collected data from 12 high school in Seoul and Kyonggi area. For this study the analytic framework of unified validity was developed which can comprehensively reflect unified validity be Messick(1995), framework for conducting a strong program of construct validation by Benson(1998), the unified validity implementation method of Rasch model suggested by Wolfe and Smith(2007a, 2007b). Furthermore, after dividing the developed analytic framework into each stage(the substantive domain), the evidence of validity of Youth Obesity Prevention Scale(YOPS) applying Health Belief Model was systematically suggested. The YOPS suggested the evidence about the substantive domain of unified validity. The developed YOPS was consist of Susceptibility, Severity, Benefits, Barriers and Cues to Action. After 3 stage in substantive domain, the components of YOPS(5factors and 28items) satisfied the unidimensionality, and the 5 point Likert scale had the significant discrimination of the respondents' response.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1319-1329
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• 2013

The purpose of this research was to develop and validate the coach-athlete relationship scale suitable to amateur golf players by applying the Rasch rating scale model. As the coach-athlete relationship scale, the Korean form of scale developed by Kim and Park (2008), which was revised based on the evidence on the basis of inspection contents, was used to conduct a survey on 217 amateur golf athletes. And the unidimensionality, which is the basic assumption of the Rasch model, was verified using the WINSTEPS program, and the appropriateness of the item category was established through the step calibration. The goodness of fit of each question was tested through the goodness-of-fit index and the differential item functioning (DIF) was estimated according to the golf career. When the goodness-of-fit index estimated for each question was 1.30 or more it was judged unfit and the significance level in the analysis was all set as.05. The results of the analysis showed that the measures variance explained by the Rasch measurement model was more (33.7%) than 20%, so the unidimensionality assumptions of the 11 questions (..hospitable posture when my coach is teaching) were satisfied. The result of analyzing the item category (7 scale) with step calibration was found to be unfit, but in the result of reanalyzing by rescoring into a 5-point scale, it was found to be fit. Particularly, in the result of estimating the goodness-of-fit using the systematized item category (5 scale), Question 10 (...my best when my coach is teaching) and Question 11 were found to be unfit, and as a result of estimating the differential functioning item according to golf career, Question 11 was found to be unevenly differentiated according to golf career. So the 5-point scale of Question 9 after eliminating the two questions which were unfit and differentiated was validated to be the coach-athlete relationship scale suitable to amateur golf athletes.