@article{ProdingerBallertBrachetal.2016, author = {Prodinger, Birgit and Ballert, C. S. and Brach, M. and Brinkhof, M. W. G. and Cieza, A. and Hug, K. and Jordan, X. and Post, M. W. M. and Scheel-Sailer, A. and Schubert, M. and Tennant, A. and Stucki, G.}, title = {Toward standardized reporting for a cohort study on functioning: The Swiss Spinal Cord Injury Cohort Study}, series = {Journal of Rehabilitation Medicine}, volume = {48}, journal = {Journal of Rehabilitation Medicine}, number = {2}, pages = {189 -- 196}, year = {2016}, abstract = {Objective: Functioning is an important outcome to measure in cohort studies. Clear and operational outcomes are needed to judge the quality of a cohort study. This paper outlines guiding principles for reporting functioning in cohort studies and addresses some outstanding issues. Design: Principles of how to standardize reporting of data from a cohort study on functioning, by deriving scores that are most useful for further statistical analysis and reporting, are outlined. The Swiss Spinal Cord Injury Cohort Study Community Survey serves as a case in point to provide a practical application of these principles. Methods and Results: Development of reporting scores must be conceptually coherent and metrically sound. The International Classification of Functioning, Disability and Health (ICF) can serve as the frame of reference for this, with its categories serving as reference units for reporting. To derive a score for further statistical analysis and reporting, items measuring a single latent trait must be invariant across groups. The Rasch measurement model is well suited to test these assumptions. Conclusion: Our approach is a valuable guide for researchers and clinicians, as it fosters comparability of data, strengthens the comprehensiveness of scope, and provides invariant, interval-scaled data for further statistical analyses of functioning.}, language = {en} } @article{ProdingerHammondTennantetal.2019, author = {Prodinger, Birgit and Hammond, A. and Tennant, A. and Prior, Y. and Tyson, S.}, title = {Revisiting the disabilities of the arm, shoulder and hand (DASH) and QuickDASH in rheumatoid arthritis}, series = {BMC Musculoskeletal Disorder}, volume = {20}, journal = {BMC Musculoskeletal Disorder}, number = {1}, pages = {41}, year = {2019}, abstract = {Background Limitations in upper limb functioning are common in Musculoskeletal disorders and the Disabilities of the Arm, Shoulder and Hand scale (DASH) has gained widespread use in this context. However, various concerns have been raised about its construct validity and so this study seeks to examine this and other psychometric aspects of both the DASH and QuickDASH from a modern test theory perspective. Methods Participants in the study were eligible if they had a confirmed diagnosis of Rheumatoid Arthritis (RA). They were mailed a questionnaire booklet which included the DASH. Construct validity was examined by fit to the Rasch measurement model. The degree of precision of both the DASH and QuickDASH were considered through their Standard Error of Measurement (SEM). Results Three hundred and thirty-seven subjects with confirmed RA took part, with a mean age of 62.0 years (SD12.1); 73.6\% (n = 252) were female. The median standardized score on the DASH was 33 (IQR 17.5-55.0). Significant misfit of the DASH and QuickDASH was observed but, after accommodating local dependency among items in a two-testlet solution, satisfactory fit was obtained, supporting the unidimensionality of the total sets and the sufficiency of the raw (ordinal or standardized) scores. Conclusion Having accommodated local response dependency in the DASH and QuickDASH item sets, their total scores are shown to be valid, given they satisfy the Rasch model assumptions. The Rasch transformation should be used whenever all items are used to calculate a change score, or to apply parametric statistics within an RA population. Significance and innovations Most previous modern psychometric analyses of both the DASH and QuickDASH have failed to fully address the effect of a breach of the local independence assumption upon construct validity. Accommodating this problem by creating 'super items' or testlets, removes this effect and shows that both versions of the scale are valid and unidimensional, as applied with a bi-factor equivalent solution to an RA population. The Standard Error of Measurement of a scale can be biased by failing to take into account the local dependency in the data which inflates reliability and thus making the SEM appear better (i.e. smaller) than the true value without bias.}, language = {en} } @article{ProdingerTennantStuckietal.2016, author = {Prodinger, Birgit and Tennant, A. and Stucki, G. and Cieza, A. and {\"U}st{\"u}n, T.B.}, title = {Harmonizing routinely collected health information for strengthening quality management in health systems: requirements and practice}, series = {Journal of Health Services Research \& Policy}, volume = {21}, journal = {Journal of Health Services Research \& Policy}, number = {4}, pages = {223 -- 228}, year = {2016}, abstract = {Objective Our aim was to specify the requirements of an architecture to serve as the foundation for standardized reporting of health information and to provide an exemplary application of this architecture. Methods The World Health Organization's International Classification of Functioning, Disability and Health (ICF) served as the conceptual framework. Methods to establish content comparability were the ICF Linking Rules. The Rasch measurement model, as a special case of additive conjoint measurement, which satisfies the required criteria for fundamental measurement, allowed for the development of a common metric foundation for measurement unit conversion. Secondary analysis of data from the North Yorkshire Survey was used to illustrate these methods. Patients completed three instruments and the items were linked to the ICF. The Rasch measurement model was applied, first to each scale, and then to items across scales which were linked to a common domain. Results Based on the linking of items to the ICF, the majority of items were grouped into two domains, Mobility and Self-care. Analysis of the individual scales and of items linked to a common domain across scales satisfied the requirements of the Rasch measurement model. The measurement unit conversion between items from the three instruments linked to the Mobility and Self-care domains, respectively, was demonstrated. Conclusions The realization of an ICF-based architecture for information on patients' functioning enables harmonization of health information while allowing clinicians and researchers to continue using their existing instruments. This architecture will facilitate access to comprehensive and consistently reported health information to serve as the foundation for informed decision-making.}, language = {en} } @article{ProdingerBallertBrinkofetal.2016, author = {Prodinger, Birgit and Ballert, C.S. and Brinkof, M. W. G. and Tennant, A. and Post, M. W. M.}, title = {Metric properties of the Spinal Cord Independence Measure - Self Report in a community survey}, series = {Journal of Rehabilitation Medicine}, volume = {48}, journal = {Journal of Rehabilitation Medicine}, number = {2}, pages = {149 -- 164}, year = {2016}, abstract = {Objective: The Spinal Cord Independence Measure - Self Report (SCIM-SR) is a self-report instrument for assessing functional independence of persons with spinal cord injury. This study examined the internal construct validity and reliability of the SCIM-SR, when administered in a community survey, using the Rasch measurement model. Methods: Rasch analysis of data from 1,549 individuals with spinal cord injury who completed the SCIM-SR. Results: In the initial analysis no fit to the Rasch model was achieved. Items were grouped into testlets to accommodate the substantial local dependency. Due to the differential item functioning for lesion level and degree, spinal cord injury-specific sub-group analyses were conducted. Fit to the Rasch model was then achieved for individuals with tetraplegia and complete paraplegia, but not for those with incomplete paraplegia. Comparability of ability estimates across sub-groups was attained by anchoring all sub-groups on a testlet. Conclusion: The SCIM-SR violates certain assumptions of the Rasch measurement model, as shown by the local dependency and differential item functioning. However, an intermediate solution to achieve fit in 3 out of 4 spinal cord injury sub-groups was found. For the time being, therefore, it advisable to use this approach to compute Rasch-transformed SCIM-SR scores.}, language = {en} } @article{MaritzEhrmannProdingeretal.2020, author = {Maritz, R. and Ehrmann, C. and Prodinger, Birgit and Tennant, A. and Stucki, G.}, title = {The influence and added value of a Standardized Assessment and Reporting System for functioning outcomes upon national rehabilitation quality reports}, series = {International Journal for Quality in Health Care}, volume = {32}, journal = {International Journal for Quality in Health Care}, number = {6}, publisher = {Oxford University Press}, address = {Oxford}, pages = {379 -- 387}, year = {2020}, abstract = {Objective To demonstrate the influence and added value of a Standardized Assessment and Reporting System (StARS) upon the reporting of functioning outcomes for national rehabilitation quality reports. A StARS builds upon an ICF-based (International Classification of Functioning, Disability and Health) and interval-scaled common metric. Design Comparison of current ordinal-scaled Swiss national rehabilitation outcome reports including an expert-consensus-based transformation scale with StARS-based reports through descriptive statistical methods and content exploration of further development areas of the reports with relevant ICF Core Sets. Setting Swiss national public rehabilitation outcome quality reports on the clinic level. Participants A total of 29 Swiss rehabilitation clinics provided their quality report datasets including 18 047 patients. Interventions Neurological or musculoskeletal rehabilitation. Main outcome measures Functional Independence Measure™ or Extended Barthel Index. Results Outcomes reported with a StARS tended to be smaller but more precise than in the current ordinal-scaled reports, indicating an overestimation of achieved outcomes in the latter. The comparison of the common metric's content with ICF Core Sets suggests to include 'energy and drive functions' or 'maintaining a basic body position' to enhance the content of functioning as an indicator. Conclusions A StARS supports the comparison of outcomes assessed with different measures on the same interval-scaled ICF-based common metric. Careful consideration is needed whether an ordinal-scaled or interval-scaled reporting system is applied as the magnitude and precision of reported outcomes is influenced. The StARS' ICF basis brings an added value by informing further development of functioning as a relevant indicator for national outcome quality reports in rehabilitation.}, language = {en} } @article{MaritzTennantFellinghaueretal.2019, author = {Maritz, R. and Tennant, A. and Fellinghauer, C. and Stucki, G. and Prodinger, Birgit}, title = {The Extended Barthel Index (EBI) can Be Reported as a Unidimensional Interval-Scaled Metric - A Psychometric Study}, series = {Physikalische Medizin, Rehabilitationsmedizin, Kurortmedizin}, volume = {29}, journal = {Physikalische Medizin, Rehabilitationsmedizin, Kurortmedizin}, number = {04}, pages = {224 -- 232}, year = {2019}, abstract = {Background: The Extended Barthel Index (EBI), consisting of the original Barthel Index plus 6 cognitive items, provides a tool to monitor patients' outcomes in rehabilitation. Whether the EBI provides a unidimensional metric, thus can be reported as a valid sum-score, remains to be examined. Objective: To examine whether the EBI can be reported as unidimensional interval-scaled metric for neurological and musculoskeletal rehabilitation. Methods: Rasch analysis of a calibration sample of 800 cases from neurological or musculoskeletal rehabilitation in 2016 in Switzerland. Results: In the baseline analysis no fit to the Rasch Model was achieved. When accommodating local dependencies with a testlet approach satisfactory fit to the Rasch Model was achieved, and an interval scale transformation table was created. Conclusion: The results support the reporting of adapted EBI total scores for both rehabilitation groups by applying the interval scaled transformation table presented in this study.}, language = {en} } @article{MaritzTennantFellinghaueretal.2019, author = {Maritz, R. and Tennant, A. and Fellinghauer, C. and Stucki, G. and Prodinger, Birgit}, title = {The Functional Independence Measure 18-item version can be reported as a unidimensional interval-scaled metric: Internal construct validity revisited}, series = {Journal of Rehabilitation Medicine}, volume = {51}, journal = {Journal of Rehabilitation Medicine}, number = {3}, pages = {193 -- 200}, year = {2019}, abstract = {Abstract Objective: Since the 1990s the Functional Independence Measure (FIM™) was believed to measure 2 different constructs, represented by its motor and cognitive subscales. The practice of reporting FIM™ total scores, together with recent developments in the understanding of the influence of locally dependent items on fit to the Rasch model, raises the question of whether the FIM™ 18-item version can be reported as a unidimensional interval-scaled metric. Design: Rasch analysis of the FIM™ using testlet approaches to accommodate local response dependency. Patients: A calibration sample containing 946 cases of data from 11,103 patients undergoing neurological or musculoskeletal rehabilitation in Switzerland in 2016. Results: Baseline analysis and the traditional testlet approach showed no fit with the Rasch model. When items were grouped into 2 testlets, fit to the Rasch model was achieved, indicating unidimensionality across all 18 items. A transformation table to convert FIM™ raw ordinal scores to the corresponding Rasch interval scaled values was created. Conclusion: This study provides evidence that FIM™ total scores represent a unidimensional set of items, supporting their use in clinical practice and outcome reporting when applying the respective transformation table. This provides a basis for standardized reporting of functioning. Lay Abstract The aim of this study was to look in detail at the FIM™, an assessment tool often used for patients undergoing rehabilitation. Some users report the FIM™ as 2 scores: one related to motor tasks, the other to cognitive tasks; others recommend reporting it as a single score including both motor and cognitive tasks. This study explored whether it is statistically meaningful to sum all the points into a single FIM™ total score. The results support the current practice of summing the points into a single total score for patients undergoing musculo-skeletal and neurological rehabilitation. The results also allowed an interval scale to be derived from the FIM™, enabling a broad range of calculations to be made using the FIM™ score, such as calculating the change in FIM™ outcomes from the time a patient is admitted to a rehabilitation clinic until their discharge.}, language = {en} } @article{ProdingerStuckiCoenenetal.2019, author = {Prodinger, Birgit and Stucki, G. and Coenen, M. and Tennant, A.}, title = {The measurement of functioning using the International Classification of Functioning, Disability and Health: comparing qualifier ratings with existing health status instruments}, series = {Disability and Rehabilitation}, volume = {41}, journal = {Disability and Rehabilitation}, number = {5}, pages = {541 -- 548}, year = {2019}, abstract = {Background: The International Classification of Functioning, Disability and Health is the international standard for describing and monitoring functioning. While the categories, the units of the classification, were not designed with measurement in mind, the hierarchical structure of the classification lends itself to the possibility of summating categories into some higher order domain. Focusing on the chapters of d4 Mobility, d5 Self-Care and d6 Domestic Life, this study seeks to ascertain if qualifiers rating of categories (0-No problem to 4-Complete problem) within those chapters can be summated, and whether such derived measurement is consistent with estimates obtained from well-known instruments which purport to measure the same constructs. Methods: The current study applies secondary analysis to data previously collected in the context of validating Core Sets for stroke, rheumatoid arthritis, and osteoarthritis. Data included qualifier-based ratings of the categories in the Core Sets, and the physical functioning sub-scale of the Short-Form 36, and the World Health Organization Disability Assessment Schedule 2.0. To examine qualifier-comparator scale item agreement Kappa statistics were used. To identify whether appropriate gradients of the comparator scales were observed across qualifier levels, an Independent Sample Median Test of the ordinal scores was deployed. To investigate the internal validity of the summated ICF categories, the Rasch model was applied. Results: Data from 2,927 subjects from Europe, Australasia, Middle East and South America were available for analysis; 36.3\% had experienced a stroke, 35.8\% osteoarthritis, and 27.9\% had rheumatoid arthritis. The items from the Short-Form 36 could not match directly the qualifier categories as the former had only 3 response options. The Kappa between World Health Organization Disability Assessment Schedule 2.0 items and categories was low. For all qualifiers, a significant (<0.001) overall gradient was observed across the comparator scales. Only in few of the World Health Organization Disability Assessment Schedule 2.0 items could no discrete level be detected. The aggregation of the qualifiers at the Chapter and higher order levels mostly revealed fit to the Rasch model. Almost all ICF qualifiers showed ordered thresholds suggesting that the current structure and response options of the qualifiers worked as intended. Conclusions: The findings of this study provide supporting evidence for the use of the professionally rated categories and associated qualifiers to measure functioning. Implication for Rehabilitation - This study provides evidence that functioning data can be collected directly with the International Classification of Functioning, Disability and Health (ICF) by using the ICF categories as items and the ICF qualifiers as rating scale. - The findings of this study show the aggregated ratings of ICF categories from the chapters d4 Mobility, d5 Self-care, and d6 Domestic life capture a broader spectrum of the construct than the corresponding summated items from the SF36-Physical Function sub-scale and the corresponding items of the World Health Organization Disability Assessment Schedule 2.0. - This study illustrates the potential of building quantitative measurement by aggregating ICF categories and their qualifier ratings into meaningful domains.}, language = {en} } @article{ProdingerTennantStucki2018, author = {Prodinger, Birgit and Tennant, A. and Stucki, G.}, title = {Standardized reporting of functioning information on ICF-based common metrics}, series = {European Journal of Physical and Rehabilitation Medicine}, volume = {54}, journal = {European Journal of Physical and Rehabilitation Medicine}, number = {1}, pages = {110 -- 117}, year = {2018}, abstract = {BACKGROUND: In clinical practice and research a variety of clinical data collection tools are used to collect information on people's functioning for clinical practice and research and national health information systems. Reporting on ICF-based common metrics enables standardized documentation of functioning information in national health information systems. The objective of this methodological note on applying the ICF in rehabilitation is to demonstrate how to report functioning information collected with a data collection tool on ICF-based common metrics. We first specify the requirements for the standardized reporting of functioning information. Secondly, we introduce the methods needed for transforming functioning data to ICF-based common metrics. Finally, we provide an example. METHODS: The requirements for standardized reporting are as follows: 1) having a common conceptual framework to enable content comparability between any health information; and 2) a measurement framework so that scores between two or more clinical data collection tools can be directly compared. The methods needed to achieve these requirements are the ICF Linking Rules and the Rasch measurement model. Using data collected incorporating the 36-item Short Form Health Survey (SF-36), the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0), and the Stroke Impact Scale 3.0 (SIS 3.0), the application of the standardized reporting based on common metrics is demonstrated. RESULTS: A subset of items from the three tools linked to common chapters of the ICF (d4 Mobility, d5 Self-care and d6 Domestic life), were entered as "super items" into the Rasch model. Good fit was achieved with no residual local dependency and a unidimensional metric. A transformation table allows for comparison between scales, and between a scale and the reporting common metric. CONCLUSIONS: Being able to report functioning information collected with commonly used clinical data collection tools with ICF-based common metrics enables clinicians and researchers to continue using their tools while still being able to compare and aggregate the information within and across tools.}, language = {en} } @article{ProdingerCoenenHammondetal.2020, author = {Prodinger, Birgit and Coenen, M and Hammond, A and K{\"u}{\c{c}}{\"u}kdeveci, AA and Tennant, A}, title = {Scale-Banking for Patient Reported Outcome Measures (PROMs) Measuring Functioning in Rheumatoid Arthritis: A Daily Activities Metric}, series = {Arthritis Care \& Research}, volume = {Online ahead of print}, journal = {Arthritis Care \& Research}, year = {2020}, abstract = {Objective: Functioning is an important outcome for rheumatoid arthritis (RA) management. Heterogeneity of respective patient-reported outcome measures (PROMs) challenges direct comparisons between their results. This study aimed to standardize reporting of such PROMs measuring functioning in RA to facilitate comparability. Methods: Common Item Non-Equivalent Groups Design (NEAT) with the Health Assessment Questionnaire (HAQ) as a common scale across data sets from various countries (incl. UK, Turkey and Germany) to establish a common metric. Other PROMs included are the Physical Function items of the Multidimensional Health Assessment Questionnaire (MDHAQ), Disabilities of Arm, Shoulder and Hand (DASH), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), World Health Organization Disability Assessment Schedule Version 2.0 (WHODAS 2.0), and four short forms (20, 10, 6, and 4 physical function items) from the Patient-Reported Outcomes Measurement Information System (PROMIS). As the HAQ includes mobility, self-care and domestic life items, this study focuses on these three domains. PROMs were described using Standard Error of Measurement (SEM) and Smallest Detectable Difference (SDD). Rasch Measurement model was used to create the common metric. Results: Range of SEM is 0.2 (MDHAQ) to 7.4 (SF36-PF). SDD revealed a range from 9.7 \% (WOMAC-RAT) to 33.5 \% (WHODAS-PF). PROMs co-calibration revealed fit to the Rasch measurement model. A transformation table was developed to allow exchange between PROMs scores. Discussion: Scores between the Daily Activity PROMs commonly used in RA can now be compared. Factors such as SEM and SDD help determine choice of PROM in clinical practice and research. Keywords: Common metric; DASH; Disability and Health; HAQ; International Classification of Functioning; Multidimensional HAQ; PROMIS-SF; Rasch measurement model; Scale banking; WHODAS 2.0; WOMAC.}, language = {en} } @article{ProdingerCoenenHammondetal.2022, author = {Prodinger, Birgit and Coenen, Michaela and Hammond, Alison and K{\"u}{\c{c}}{\"u}kdeveci, Ay{\c{s}}e A. and Tennant, Alan}, title = {Scale Banking for Patient-Reported Outcome Measures That Measure Functioning in Rheumatoid Arthritis: A Daily Activities Metric}, series = {Arthritis Care \& Research}, volume = {74}, journal = {Arthritis Care \& Research}, number = {4}, pages = {579 -- 587}, year = {2022}, abstract = {Objective Functioning is an important outcome for the management of rheumatoid arthritis (RA). Heterogeneity of respective patient-reported outcome measures (PROMs) challenges direct comparisons between their results. This study aimed to standardize reporting of such PROMs measuring functioning in RA to facilitate comparability. Methods Common-item nonequivalent group design with the Health Assessment Questionnaire (HAQ) as a common scale across data sets from various countries (including the UK, Turkey, and Germany) to establish a common metric was used. Other PROMs included are the physical function items of the Multidimensional HAQ (MDHAQ), the Disabilities of the Arm, Shoulder, and Hand questionnaire, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the World Health Organization Disability Assessment Schedule II (WHODAS II), the Medical Outcomes Study Short Form 36 (SF-36) health survey, and 4 short forms (20, 10, 6, and 4 physical function items) from the Patient-Reported Outcomes Measurement Information System. As the HAQ includes mobility, self-care, and domestic life items, this study focuses on these 3 domains. PROMs were described using standard error of measurement (SEM) and smallest detectable difference (SDD). A Rasch measurement model was used to create the common metric. Results The range of the SEM was 0.2 (MDHAQ) to 7.4 (SF-36 health survey physical functioning domain). The SDD revealed a range from 9.7\% (WOMAC rating scale) to 33.5\% (WHODAS physical functioning domain). PROMs co-calibration revealed fit to the Rasch measurement model. A transformation table was developed to allow exchange between PROM scores. Conclusion Scores between the daily activity PROMs commonly used in RA can now be compared. Factors such as SEM and SDD help to determine the choice of a PROM in clinical practice and research.}, language = {en} } @article{ProdingerCoenenHammondetal.2020, author = {Prodinger, Birgit and Coenen, Michaela and Hammond, Alison and K{\"u}{\c{c}}{\"u}kdeveci, Ayse A. and Tennant, Alan}, title = {Scale-Banking for Patient Reported Outcome Measures (PROMs) Measuring Functioning in Rheumatoid Arthritis: A Daily Activities Metric}, series = {Arthritis Care \& Research}, journal = {Arthritis Care \& Research}, year = {2020}, abstract = {Objective: Functioning is an important outcome for rheumatoid arthritis (RA) management. Heterogeneity of respective patient-reported outcome measures (PROMs) challenges direct comparisons between their results. This study aimed to standardize reporting of such PROMs measuring functioning in RA to facilitate comparability. Methods: Common Item Non-Equivalent Groups Design (NEAT) with the Health Assessment Questionnaire (HAQ) as a common scale across data sets from various countries (incl. UK, Turkey and Germany) to establish a common metric. Other PROMs included are the Physical Function items of the Multidimensional Health Assessment Questionnaire (MDHAQ), Disabilities of Arm, Shoulder and Hand (DASH), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), World Health Organization Disability Assessment Schedule Version 2.0 (WHODAS 2.0), and four short forms (20, 10, 6, and 4 physical function items) from the Patient-Reported Outcomes Measurement Information System (PROMIS). As the HAQ includes mobility, self-care and domestic life items, this study focuses on these three domains. PROMs were described using Standard Error of Measurement (SEM) and Smallest Detectable Difference (SDD). Rasch Measurement model was used to create the common metric. Results: Range of SEM is 0.2 (MDHAQ) to 7.4 (SF36-PF). SDD revealed a range from 9.7 \% (WOMAC-RAT) to 33.5 \% (WHODAS-PF). PROMs co-calibration revealed fit to the Rasch measurement model. A transformation table was developed to allow exchange between PROMs scores. Discussion: Scores between the Daily Activity PROMs commonly used in RA can now be compared. Factors such as SEM and SDD help determine choice of PROM in clinical practice and research.}, language = {en} } @article{ProdingerO'ConnorStuckietal.2017, author = {Prodinger, Birgit and O'Connor, R.J. and Stucki, G. and Tennant, A.}, title = {Establishing score equivalence of the Functional Independence Measure (FIM™) motor scale and the Barthel Index, utilising the International Classification of Functioning, Disability and Health (ICF) and Rasch Measurement Theory}, series = {Journal of Rehabilitation Medicine}, volume = {49}, journal = {Journal of Rehabilitation Medicine}, number = {5}, pages = {416 -- 422}, year = {2017}, abstract = {Introduction: Two widely used outcome measures to assess functioning in neurological rehabilitation are the Functional Independence Measure (FIM™) and the Barthel Index. The current study aims to establish the equivalence of the total score of the FIM™ motor scale and the Barthel Index through the application of the International Classification of Functioning, Disability and Health, and Rasch measurement theory. Methods: Secondary analysis of a large sample of patients with stroke, spinal cord injury, and multiple sclerosis, undergoing rehabilitation was conducted. All patients were assessed at the same time on both the FIM™ and the Barthel Index. The International Classification of Functioning, Disability and Health Linking Rules were used to establish conceptual coherency between the 2 scales, and the Rasch measurement model to establish an exchange of the total scores. Results: Using the FIM™ motor scale, items from both scales linked to the International Classification of Functioning, Disability and Health d4 Mobility or d5 Self-care chapters. Their co-calibration satisfied the assumptions of the Rasch model for each of 3 diagnostic groups. A ceiling effect was observed for the Barthel Index when contrasted against the FIM™ motor scale. Conclusion: Having a Rasch interval metric to transform scores between the FIM™ motor scale and Barthel Index is valuable for monitoring functioning, meta-analysis, quality audits and hospital benchmarking.}, language = {en} } @article{ProdingerStammPeterssonetal.2016, author = {Prodinger, Birgit and Stamm, T. and Petersson, D. and Stucki, G. and Tennant, A.}, title = {Toward a standardized reporting of outcomes in hand osteoarthritis: Developing a common metric of outcome measures commonly used to assess functioning.}, series = {Arthritis Care \& Research}, volume = {68}, journal = {Arthritis Care \& Research}, number = {8}, pages = {1115 -- 1127}, year = {2016}, abstract = {Objective Functioning is an important outcome in hand osteoarthritis (OA). The heterogeneity of patient-reported outcome measures (PROMs) available challenges the direct comparability of information collected by these instruments. This study aimed to examine whether it is possible to achieve metric equivalence of PROMs commonly used to measure functioning in people with hand OA. Methods A secondary analysis of data from 253 persons who participated in the Vienna Hand Osteoarthritis Cohort Study was conducted applying the Rasch measurement model. Participants completed the Health Assessment Questionnaire, the Australian/Canadian Index for Hand Osteoarthritis, the Functional Index for Hand Osteoarthritis (FIHOA), and the Cochin Scale. The assumptions of stochastic ordering, local independence, unidimensionality, and invariance were tested for each scale independently before the scales were co-calibrated onto a common metric. Results Except for the FIHOA, all measures indicated issues of local dependency in the initial analyses. After accommodating those with testlets, all scales satisfied the assumptions of the Rasch model (χ2 > 0.05). Marginal misfit in 2 items was found in the FIHOA, but this did not disturb person estimates. As the 4 scales form a common metric that satisfies the assumptions of the Rasch model, the scores can be equated. Conclusion The scores of the 4 hand function measures can be transformed to a common 0-100 metric, such that scores can be interchanged. A user-friendly transformation table enables clinicians and researchers to have access to the common metric by simply adding up the total score for each instrument and identifying the corresponding transformed score on the common metric.}, language = {en} } @article{ProdingerKuecuekdeveciKutlayetal.2020, author = {Prodinger, Birgit and K{\"u}{\c{c}}{\"u}kdeveci, AA and Kutlay, S and Elhan, AH and Kreiner, S and Tennant, A}, title = {Cross-diagnostic scale-banking using Rasch analysis: Developing a common reference metric for generic and health condition-specific scales in people with rheumatoid arthritis and stroke.}, series = {Journal of Rehabilitation Medicine}, journal = {Journal of Rehabilitation Medicine}, year = {2020}, abstract = {Abstract Objectives: To develop a common reference metric of functioning, incorporating generic and health condition-specific disability instruments, and to test whether this reference metric is invariant across 2 health conditions. Design: Psychometric study using secondary data analysis. Firstly, the International Classification of Functioning, Disability and Health (ICF) Linking Rules were used to examine the concept equivalence between the World Health Organization Disability Assessment Schedule (WHODAS 2.0), Health Assessment Questionnaire (HAQ), and Functional Independence Measure (FIMTM). Secondly, a scale-bank was developed using a reference metric approach to test-equating, based on the Rasch measurement model. Participants: Secondary analysis was performed on data from 487 people; 61.4\% with rheumatoid arthritis and 38.6\% with stroke. Results: Three sub-domains of the WHODAS 2.0 and all items of the HAQ and FIMTM motor mapped on to the ICF chapters d4 Mobility, d5 Self-care and d6 Domestic life. Test-equating of these scales resulted in good model fit, indicating that a scale bank and associated reference metric across these 3 instruments could be created. Conclusion: This study provides a transformation table to enable direct comparisons among instruments measuring physical functioning commonly used in rheumatoid arthritis (HAQ) and stroke (FIMTM motor scale), as well as in people with disability in general (WHODAS 2.0). Keywords: FIM; Functional Independence Measure; HAQ; Health Assessment Questionnaire; WHODAS 2.0; World Health Organization Disability Assessment Schedule; outcome assessment; rheumatoid arthritis; stroke; psychometrics.}, language = {en} }