Person Separation Index Research Articles

Psychometric Validity of the Visual Function Index in Leber Hereditary Optic Neuropathy.

The purpose of this study was to determine the psychometric validity of the Visual Function Index (VF-14) for use by patients with Leber hereditary optic neuropathy (LHON). Rasch analysis was conducted in two stages using data for 196 individuals (74.5% male) carrying one of the three primary LHON mutations and affected by vision loss. In stage 1, scale unidimensionality, scale-to-sample targeting, response category threshold ordering, item fit statistics, local dependency, and reliability were assessed. In stage 2, iterative post-hoc revisions of the VF-14 structure (VF-14R) were applied and psychometrically re-evaluated. Issues identified with the VF-14 included disordered response thresholds (12/14 items), local dependency (10/91 pairwise dependencies), and evidence of multidimensionality. However, the distribution of person estimates and item thresholds were fairly well matched, only one item showed misfit to the Rasch model, and there was good reliability (Person Separation Index 0.84). Rasch-informed VF-14 revisions included removing both driving items and the misfitting sports item, rescoring response options across all items by merging two response categories, and accounting for the dependency between two reading items. The VF-14R demonstrated improved psychometric validity. Clinicians and researchers using the VF-14 with LHON patients should be aware of its limitations. Compared to the original version, the proposed Rasch-based structure of the VF-14R appears to offer improved psychometric performance and interpretation of vision-related activity limitation. The original version of the VF-14 exhibits several limitations that undermines its psychometric validity as a patient-reported outcome measure for patients with LHON.

Catquest-9SF questionnaire: validation of the Portuguese version using the Rasch analysis.

The aim of this study was to validate the Portuguese version of Catquest-9SF through its application in a native Brazilian population with cataracts and to determine the correlation of the questionnaire scores with preoperative visual acuity. A prospective study was conducted to validate the Catquest-9SF questionnaire, which was translated and back-translated, generating a final version in Portuguese. A total of 120 Brazilian patients awaiting cataract surgery were recruited to answer the questionnaire and to document their preoperative data and visual acuity. The Rasch analysis was used to assess the instrument's psychometric properties. The Portuguese version of Catquest-9SF demonstrated an acceptable adjustment of the items (item fit statistics ranging from 0.7 to 1.3), unidimensionality (principal component analysis), and good organization in the item response categories (thresholds of the categories: -2.79, 0.57, and 2.22, respectively). The questionnaire contains items with stable relationships if considered at the same level of visual impairment in the comparison between the two groups (absence of differential item functioning). The separation of people (person separation index, 3.07) was adequate. The visual acuity in the logarithm of the minimum angle of resolution (logMAR) in the best eye with the best optical correction showed a statistically significant correlation with the Catquest-9SF logit score (r=0.282 and p=0.004). The Portuguese version of Catquest-9SF presents evidence of validity and reliability, in addition to being linguistically and culturally understandable for Portuguese-speaking patients born in Brazil. The questionnaire is easy to understand and quick to apply, as it could adequately estimate the subjective visual functioning in patients with cataracts. We found a significant correlation between visual acuity and the questionnaire score.

The osteoarthritis knowledge scale.

Accurate knowledge is central to effective self-care of osteoarthritis (OA). This study aimed to assess the measurement properties of the Osteoarthritis Knowledge Scale (OAKS) with versions for the hip and knee. Participants with hip OA (n=144), knee OA (n=327), and no OA (n=735) were recruited. Rasch analysis was conducted to assess psychometric properties using data from all participants with hip OA and 144 randomly selected participants with either knee OA or no OA. Test-retest reliability and measurement error were estimated among those with hip (n=51) and knee (n=142) OA. Four items from the draft scales were deleted following Rasch analysis. The final 11-item OAKS was unidimensional. Item functioning was not affected by gender, age, educational level, or scale version (hip or knee). Person separation index was 0.75. Test-retest intraclass correlation coefficient was 0.81 (95% CI 0.74, 0.86; hip version 0.66 [0.47, 0.79]; knee version 0.85 (0.79, 0.90)). Smallest detectable change was 9 points (scale range 11-55; hip OA version 11 points; knee OA version 8 points). The OAKS is a psychometrically adequate, unidimensional measure of important OA knowledge that can be used in populations with and without hip and knee OA. Caution is needed when using with populations with only hip OA as test-retest reliability of the hip version did not surpass the acceptable range.

Further psychometric evaluation of the Structured Multidisciplinary Work Evaluation Tool (SMET) questionnaire: Practical implications in healthcare settings.

Scientific research has identified a lack of psychometrically well-tested methods for evaluation of the work environment in healthcare settings. The Structured Multidisciplinary Work Evaluation Tool (SMET) questionnaire has been evaluated and has shown good content validity, as well as intra-rater and test-retest reliability. There are, however, still unknowns regarding the psychometric properties. If the SMET questionnaire is to be used in practical occupational health service (OHS) work and scientific research in healthcare settings, further psychometric evaluation is needed. The aim of this study was to gain further understanding of the psychometric properties of the SMET questionnaire when used in research and clinical OHS practice in healthcare settings. The psychometric evaluation was conducted using classical test theory (Cronbach's alpha, explorative factor analysis) and Rasch analysis (measurement targeting, category threshold order, person separation index) on data previously collected in development projects within the healthcare sector. The results support the use of the SMET questionnaire as a psychometrically well-tested method for evaluation of the work environment in healthcare settings. They support the use of the initial 1-10 scale since all 10 steps are used. The results also support the trichotomization procedure since the trichotomized scale captures the construct of the work environment with good measurement targeting and good category threshold order. The results of this study support the use of the SMET questionnaire as a psychometrically well-tested method for a broad multifactorial evaluation of the work environment in healthcare settings.

Cross-Linking Improves the Quality of Life of People With Keratoconus: A Cross-Sectional and Longitudinal Study From the Save Sight Keratoconus Registry.

The purpose of this study was to comprehensively evaluate the patient-reported quality-of-life (QoL) outcomes after corneal cross-linking for keratoconus. This Save Sight Keratoconus Registry study used cross-sectional and longitudinal designs. For the cross-sectional study, 532 patients with keratoconus (mean age 30.9 ± 11.9 years; 31.6% female) completed the Keratoconus Outcomes Research Questionnaire (KORQ) and 343 patients with keratoconus (mean age 28.3 ± 10.7 years; 32.7% female) completed the Impact of Vision Impairment (IVI) questionnaires. Similarly, for the longitudinal study, 39 patients (mean age 24.2 ± 8.4 years; 23.1% female) completed the KORQ and 16 patients (mean age 27.9 ± 17.1 years; 50.0% female) completed the IVI questionnaire before and after 6 months of cross-linking. The QoL data were analyzed using the Andrich Rating Scale Model of Rasch analysis. For both cross-sectional and longitudinal studies, the KORQ and IVI scales demonstrated satisfactory psychometric properties [ordered and well-spaced categories, variance explained by the measure 52%-73%, person separation index 2.4-3.9, and fit statistics <1.3 (most cases)]. The patients who had not undergone corneal cross-linking had worse mean activity limitation than those with cross-linking ( P = 0.008). However, the differences in symptoms and emotional scores between the groups were not statistically significant (both P > 0.05). The longitudinal study showed that cross-linking was associated with improved activity limitation, symptoms, and emotional scores. The KORQ and IVI are psychometrically robust tools to evaluate the QoL outcomes of corneal cross-linking. Cross-linking is associated with improved activity limitation, symptoms, and emotional status.

WHO Functioning and Disability Disaggregation (FDD11) tool: a reliable approach for disaggregating data by disability

BackgroundThere is a global scarcity of good quality disability data, which has contributed to a lack of political will to address the challenges that persons with disabilities face. The current paper proposes a way forward to overcome this gap by demonstrating the psychometric properties of the World Health Organization Functioning and Disability Disaggregation Tool (FDD11) - a brief disability disaggregation instrument that countries can use.ResultsThe study demonstrated that FDD11 is a valid and reliable tool. Unidimensionality of the scale produced by each calibration was supported by the factor analysis performed. The analysis indicated good fit of the items, and targeting of the items was deemed to be sufficient. The person separation index was 0.82, indicating good reliability of the final scale.ConclusionFDD11 provides a good opportunity to researchers and governments to capture good quality disability data and to disaggregate existing data by disability. The tool can facilitate low- and middle-income countries in their efforts to develop evidenced-based policies to address any barriers faced by persons with disabilities, to monitor the implementation of the Convention on the Rights of Persons with Disabilities and the Sustainable Development Goals, and to take stock of the challenges that still remain.

Catquest-9SF questionnaire: Validation in a Greek-speaking population using Rasch analysis.

The Catquest-9SF questionnaire is a tool measuring visual disability and vision-related limitation in patients' daily activities. The primary objective of this study was the validation of Catquest-9SF in a Greek-speaking cataract population. The questionnaire was translated into Greek and translated back into English. A pre-final Greek version was formed and tested by 10 Greek-English bilingual participants and by the translation team, and the final version was produced. Patients scheduled for cataract surgery completed the questionnaire preoperatively and postoperatively. Rasch analysis was performed for the assessment of the Catquest-9SF psychometric properties, including response category ordering, item fit statistics, principal components analysis, precision, differential item functioning and targeting for preoperative and postoperative data collectively. A total of 100 (55 men, 45 women, mean age = 71.94±6.63) cataract patients completed the Greek version of Catquest-9SF questionnaire preoperatively and postoperatively. Rasch analysis showed a significant improvement in the median person Rasch score from -1.49 preoperatively to -4.71 logits postoperatively, while the effect size was 1.3. Unidimensionality was confirmed since infit and outfit mean square values varied between 0.66 and 1.37. Rasch analysis showed good precision and separation ability (Person Separation Index of 3.28, and Person Reliability of 0.92). Four response categories were found for all items. The item-person means difference was -1.83 logits. The difference between preoperative and postoperative Catquest-9SF logit score was positively correlated with preoperative Catquest-9SF logit score (coeff. = 0.798, p<0.0001) and negatively correlated with postoperative spherical equivalent (coeff. = -0.825, p = 0.011). The Greek version of Catquest-9SF proved to be reliable, valid, unidimensional and responsive to changes after cataract surgery presenting good psychometric properties for cataract patients. Some postoperative mistargeting was found indicating that the tasks were easily performed by respondents after cataract surgery. NCT05323526 -retrospectively registered.

A Rasch model analysis of the TPACK instrument in the creative teaching of primary mathematics teachers

Utilising the Technological Pedagogical Content Knowledge (TPACK) instrument, mathematics teachers were evaluated on their level of TPACK in their creative teaching practices. Using Rasch model analysis, this study aimed to assess the validity and reliability of the TPACK instrument. A 30-item survey with a 5-point Likert scale was given at random to 77 primary school teachers. In order to analyse the data and evaluate the instrument using the Rasch model analysis test, including the item and person separation and reliability index, misfit items, item polarity and unidimensionality, Winsteps 5.2.2.0 software was used. The findings demonstrated a significant Cronbach's Alpha (KR20). In conclusion, this TPACK instrument has high validity and reliability for assessing knowledge in the creative teaching of mathematics teachers. Keywords: Creative teaching, mathematics, Rasch model analysis, teachers.

Validation of the Pediatric Quality of Life Inventory 3.0 Cerebral Palsy Module (Parent Form) for use in Türkiye.

This study was planned to test the reliability and validity of the Turkish version of the Pediatric Quality of Life Inventory (PedsQL) 3.0 cerebral palsy (CP) module (parent form) in children with CP. In the validation study conducted between June 2007 and June 2009, 511 children (299 normal children, 212 children with CP) were assessed by the seven scales of PedsQL [daily activities (DA), school activities (SA), movement and balance (MB), pain and hurt (PH), fatigue (F), eating activities (EA), and speech and communication (SC)]. Reliability was tested by internal consistency and person separation index (PSI); internal construct validity by Rasch analysis and external construct validity by correlation with the Gross Motor Function Classification System (GMFCS) and Functional Independence Measure for Children (WeeFIM). Only 13 children with CP completed the inventory by themselves and thus were excluded. Consequently, 199 children with CP (113 males, 86 females; mean age: 7.3±4.2 years; range, 2 to 18 years) and 299 normal children (169 males, 130 females; mean age: 9.4±4.0 years; range, 2 to 17 years) were included in the final analysis. Reliabilities of the seven scales of the PedsQL 3.0 CP module were adequate, with Cronbach's alphas between 0.66 and 0.96 and the PSI between 0.672 and 0.943 for the CP group. In Rasch analysis, for each scale, items showing disordered thresholds were rescored; then testlets were created to overcome local dependency. Internal construct validity of the unidimensional seven scales was good with the mean item fit of -0.107±1.149, 0.119±0.818, 0.232±1.069, -0.442±0.672, 0.221±0.554, -0.091±0.606, and -0.333±1.476 for DA, SA, MB, PH, F, EA, and SC, respectively. There was no differential item functioning. External construct validity of the instrument was confirmed by expected moderate to high correlations with WeeFIM and GMFCS (Spearman's r=0.35-0.89). Turkish version of the PedsQL 3.0 CP module is reliable, valid, and available for use in clinical setting to evaluate health-related quality of life of children with CP.

Using Rasch measurement theory to explore the fitness for purpose of the genetic counseling outcome scale: a tale of two scales.

The genetic counseling outcome scale (GCOS-24) is commonly used in clinical genetics to measure patient empowerment; however, there is inconclusive psychometric evidence about this scale. Using data from an urban Canadian clinic where the GCOS-24 is routinely administered before (T1) and 1month after (T2) genetic counseling, we used Rasch measurement theory (RMT) to test the ordering of response option thresholds, fit, spread of item locations, residual correlations, person separation index (PSI), and stability across time. Data from 379 participants showed that the original GCOS-24 items had poor fit to the Rasch model (χ2 = 367.8, p < 0.001). Two models emerged that demonstrated excellent fit to the Rasch model. In Model 1, the response scale options were collapsed and 8 items were removed, leading to an excellent fit to the Rasch model (χ2 = 112.4, df = 144, p = 0.975), good reliability (rp = 0.82), and responsiveness to change (mean = 0.75 logits, F = 125.68, p < 0.001). In Model 2, the response scale options were collapsed, 3 items were removed, and the scale divided into two sets (GCOS-Pos, GCOS-Neg). The GCOS-Pos set showed excellent overall fit to the Rasch model (χ2 = 92.5, df = 90, p = 0.407), good reliability (rp = 0.73), and responsiveness to change (mean = 0.74 logits, F = 80.12, p < 0.001). The GCOS-Neg set showed excellent overall fit to the Rasch model (χ2 = 84.55, df = 97, p = 0.81), but poor reliability (rp = 0.19) and small, but significant responsiveness to change (mean = 0.19 logits, F = 28.73, p < 0.001). These models show that there are psychometric issues with the GCOS-24 scale, and our study provides options for how to measure empowerment more robustly.

Validation and interval scale transformation of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients undergoing knee arthroplasty, using the Rasch model

ObjectivesInterval scale reduce measurement bias compared to ordinal scale. We aimed to evaluate the fit of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to the Rasch model and derive the transformation table for interval scale measurement. MethodsData from osteoarthritis patients listed for knee arthroplasty (KA) pre-operatively, and at 6- and 12- months post-operative was used. WOMAC was calibrated for fit to the Rasch model for monotonicity, homogeneity, local item independence and absence of differential item functioning (DIF) in a randomly selected 900 patients, 300 from each time point; parameter estimates were then imported into the full data set. Responsiveness was reported through Standard Error of Measurement (SEM); Smallest Detectable Difference (SDD), %SDD and effect sizes (ES) between baseline and 6-months. WOMAC was transformed from ordinal to interval values. Results1136 patients (mean age 65.9 years, 69.9% female) were included. WOMAC pain (0−20), function (0−68) and total scores (0−96) had adequate fit to Rasch model with good reliability (Person Separation Index: 0.76, 0.80 and 0.79). No item deletion was required. The SEM, SDD, %SDD and ES of WOMAC total were 4.4, 6.9, 10.1, and 1.97. No significant DIF was seen for age, sex, body mass index, type of KA, languages, and education level. WOMAC pain, function and total scores were transformed to interval scales. ConclusionWOMAC total, pain and function scales had adequate fit to the Rasch model, providing unidimensional measure with good reliability and responsiveness. Transformation of WOMAC to interval scale measurement is applicable to other studies.

Catquest-9SF questionnaire shows greater visual functioning in bilateral cataract populations: A prospective study.

Visual functioning evaluated by the Catquest-9SF questionnaire has shown to be a valid measure for assessing a patient's prioritization for cataract surgery. This study adapted Catquest-9SF for visual function outcomes post uni-lateral cataract surgery or bi-lateral cataract surgery. Visual functioning was assessed before and after uni-lateral or bi-lateral cataract surgery using the Catquest-9SF questionnaire. Patients were enrolled to this study prior to their cataract surgery between March 29 and April 30, 2021 at Shellharbour Hospital, Australia. Catquest-9SF questionnaires were completed prior to and 3 months post surgery. Resulting data were assessed for fit to a Rasch model using WINSTEPS software (version 4.2.0). Catquest-9SF data analysis of Chi-square, Wilcoxon sum test, and Fischer's test were performed in R (version 4.1.0). P value &lt;.05 was considered statistically significant. Sixty-one patients (mean age = 73.2 years, 62% female) were included for analysis. Catquest-9SF response thresholds, adequate precision (person separation index = 2.58, person reliability = 0.87, Cronbach's alpha = 0.74), uni-dimensionality, and no misfits (infit range 0.65-1.33; outfit range 0.64-1.31) were recorded. The mean of item calibration for patients was -0.22 post-operatively. There was significant (P &lt;.05) improvement (16.3%) in visual functions across all nine Catquest 9-SF items. There was a significant mean visual function difference between patients with uni-lateral (10.1%) and bi-lateral cataract surgery (22.3%) pre-operatively and post-operatively. The Catquest-9SF questionnaire showed excellent psychometric properties and can assess visual functioning in an Australian population. There was a significant improvement in patient visual function post cataract surgery and higher functioning with bi-lateral cataract surgery.

Validating the Cognitive Diagnostic Assessment and Assessing Students’ Mastery of ‘Parallel and Perpendicular Lines’ Using the Rasch Model

‘Parallel and Perpendicular Lines’ is an important topic that serves as a basis for the learning of a more advanced geometric concept in later years. Yet, this topic is hard to master by the students. To pinpoint students’ weaknesses in this topic, this study sought to develop a cognitive diagnostic assessment (CDA) to assess students’ mastery of ‘Parallel and Perpendicular Lines’. The validation of the CDA and the use of CDA in measuring students’ mastery of ‘Parallel and Perpendicular Lines’ was documented in this article. The content validation involved two subject matter experts, while the pilot test involved 154 Year Four students from Kedah state of Malaysia selected using cluster sampling. The experts' consensus on the relevancy of test items was captured by calculating the content validity index. The psychometric properties of items and reliability of assessment were analysed based on Rasch Measurement Model. The validity of the assessment content was supported with an acceptable content validity index of 1.00 (&amp;gt;.80). The findings of Rasch analysis span across all ranges of abilities level and hence fit students’ competence well. With an acceptable person separation index of 1.58 (&amp;gt; 1.50), person separation reliability of .74 (&amp;gt;.70), and KR-20 coefficient of .78 (&amp;gt;.70), the CDA developed is reliable. The findings of assessing students’ mastery level highlighted their weaknesses in defining the properties of perpendicular lines and drawing perpendicular lines. The findings of this study would encourage practitioners to utilise it in the mathematics classroom for diagnosing students’ weaknesses and hence plan for remedial instruction.

Development of Test-Taking Strategies Scale: High School and Undergraduate Form

Test-taking strategies are discussed in the literature as an important factor affecting test scores, and are recommended to be taken into consideration regarding the validity of tests. Although studies have been conducted for more than a quarter of a century, no agreement has yet been reached as to the dimensions of test-taking strategies. The aim of this study is to develop a valid and reliable test-taking strategies scale for undergraduate and high school students who experience intensive exam periods. In the scale prepared for this purpose, we consider tests containing different item types and focus on pre-test, during-test and post-test strategies, excluding test-preparation. Two separate forms of test-taking strategies at high school (27 items) and undergraduate levels (18 items) were developed using promising measurement theories and models. Results indicated that the Person Separation Index, as a reliability index, was calculated as .88 for the high-school form and .93 for the undergraduate form. This study is significant in presenting valid and reliable tools for measuring test-taking strategies, and is considered an exemplary research that uses Partial Credit Model for Likert-type scale development.

Rasch analysis of the 32-item motor function measure in ambulant patients with Duchenne muscular dystrophy

Objective This study analyzed the 32-item Motor Function Measure in a cohort of ambulatory patients with Duchenne muscular dystrophy using Rasch measurement methods. Design This is a psychometric study. Setting Rehabilitation centre of a large public children's hospital in Shenzhen, China. Participants Data from 176 genetically confirmed ambulant patients with Duchenne muscular dystrophy (mean age 7.3 years, SD 2.3 years, range 3.1–13.1 years) were analyzed. Results Rasch analyses supported the Motor Function Measure domain D1 as a reliable (person reliability = 0.88, person separation index = 2.71) and valid (acceptable targeting, little misfit, minimal category disordering) measure in ambulant patients with Duchenne muscular dystrophy. Remodelling the domain D1 by collapsing item 25 from 4 to 3 response categories addressed the problematic disordered thresholds, resulting in a rebuilt domain D1 with enhanced measurement properties. However, findings for domains D2 and D3 did not fulfil most Rasch model expectations. There were disordered thresholds for most items in domains D2 and D3, with low reliability coefficients, item mistargeting and misfit, and large ceiling effects. Conclusion Rasch analyses confirmed that the Motor Function Measure domain D1 was reliable and valid and provided a unidimensional measure for motor function in ambulant Duchenne muscular dystrophy patients. Accuracy of measurement had been enhanced through remodelling, and a rebuilt domain D1 with category collapsing for item 25 was proposed. The analysis revealed multiple limitations of the domains D2 and D3 that certain essential psychometrics were poorly met and, therefore, should be used with caution in this patient group.

Psychometrics of the Physical Resilience Scale in Older Adults Living with Dementia: Proxy Responses.

Objectives: The purpose of this study was to determine if proxies can complete the Physical Resilience Scale for older adults living with dementia. Methods: This was a descriptive study using Rasch analysis and baseline data from the Function Focused Care for Acute Care Using the Evidence Integration Triangle trial. The first 240 patients living with dementia were included in this analysis. Results: There was evidence of reliability based on person and item separation index. There was no evidence of Differential Item Functioning (DIF) between genders and a DIF by race on Item 7. Validity was supported based on items fitting the model with the exception of one item, and a significant relationship between physical resilience and pain and function. Discussion: There is some evidence that the Physical Resilience Scale is reliable and valid when completed by proxy reports. Future use should remove one of the items due to redundancy.

Measuring COVID-19 health literacy: validation of the COVID-19 HL questionnaire in Spain

BackgroundThe COVID-19 pandemic has highlighted the importance of health literacy to make informed preventive decisions. A specific COVID-19 health literacy questionnaire (CHL-Q) is included in the COVID-19 Snapshot Monitoring WHO initiative to conduct behavioral insights studies related to COVID-19. The objective was to assess the psychometric properties of a Spanish version of the COVID-19 Health Literacy Questionnaire (CHL-Q).MethodsData quality, acceptability, internal consistency, and construct and structural validity were analyzed. A Rasch analysis was also performed. This cross-sectional, observational study was conducted on the Spanish general population after the first wave of the pandemic and after the end of the general lockdown by an online survey agency. 1033 participants (inclusion criteria were being 18 years or older and living in Spain), was extracted from a panel of approximately 982,000 participants. The sampling was stratified matching the Spanish general population in terms of age, gender, and area of residence. The CHL-Q includes 9 items and assesses people's knowledge, motivation and competencies to access, understand, evaluate, and apply information about COVID-19 in order to make informed decisions.ResultsCHL-Q index presented a mean of 33.89 (SD = 9.4), and good fit to the Rasch model (χ2(32) = 34.672, p = 0.342, person separation index = 0.77), with ordered thresholds, unidimensionality, item local independence, and no item bias by sex, age or education level. The CHL-Q showed significant different scores by level of education, experience of infection, confusion related to COVID-19 information and adherence to preventive measures. We found a statistically significant correlation between the CHL-Q index and the total number of preventive measures adopted, COVID-19 knowledge, and information seeking behaviour. The Cronbach´s alpha was 0.87 and the item total corrected correlation, 0.49–0.68.ConclusionsThe Spanish version of CHL-Q is a short, adequate, and reliable instrument to measure COVID-19 related health literacy in the Spanish general population. Measuring the CHL in the population can be useful to evaluate whether public authorities, media and the medical and scientific community have been able to reach the population to offer the information in the terms they need it.

Properties of Patient-Reported Outcome Measures in Recessive Stargardt Disease

Introduction: The study aimed to explore the psychometric properties of the National Eye Institute Visual Function Questionnaire (NEI VFQ) and Impact of Vision Impairment (IVI) profile in recessive Stargardt disease (STGD1). Methods: The NEI VFQ-25 and IVI-28 were administered to individuals with STGD1. Responses were analyzed following psychometrically established dimension structures of the NEI VFQ (visual function [VF] subscale; socioemotional [SE] subscale) and of the IVI (functional [F] subscale; emotional [E] subscale). We analyzed internal consistency, dimensionality, item fit, and differential item functioning (DIF), using latent trait models. Criterion validity was assessed using Pearson correlation coefficients. Results: Seventy-one participants (42 females, 29 males; mean age, 44 ± 19 years) were included. Self-reported difficulty levels were lower than the mean difficulty of items in both instruments. Person reliability and person separation index of the instruments were 0.85 and 2.40 (NEI VFQ-VF), 0.69 and 1.49 (NEI-VFQ-SE), 0.88 and 2.77 (IVI-F), and 0.72 and 1.62 (IVI-E). No items showed misfit at a level distorting the measurement system. One IVI item showed DIF by gender but was retained as person measures were largely unaffected by its removal. NEI VFQ-VF and IVI-F as well as NEI VFQ-SE and IVI-E were positively correlated (r = 0.79 and 0.64, respectively). Conclusion: The NEI VFQ and IVI have acceptable psychometric properties in STGD1 with the IVI allowing more sensitive person stratification. Targeting of questionnaires to individuals with STGD1 might be improved by including additional content domains specific to the disease.

The HLS19-COM-P, a New Instrument for Measuring Communicative Health Literacy in Interaction with Physicians: Development and Validation in Nine European Countries.

Background: Sufficient communicative health literacy (COM-HL) is important for patients actively participating in dialogue with physicians, expressing their needs and desires for treatment, and asking clarifying questions. There is a lack of instruments combining communication and HL proficiency. Hence, the aim was to establish an instrument with sufficient psychometric properties for measuring COM-HL. Methods: The HLS19-COM-P instrument was developed based on a conceptual framework integrating HL with central communicative tasks. Data were collected using different data collection modes in nine countries from December 2019 to January 2021 (n = 18,674). Psychometric properties were assessed using Rasch analysis and confirmatory factor analysis. Cronbach’s alpha and Person separation index were considered for reliability. Results: The 11-item version (HLS19-COM-P-Q11) and its short version of six items (HLS19-COM-P-Q6) fit sufficiently the unidimensional partial credit Rasch model, obtained acceptable goodness-of-fit indices and high reliability. Two items tend to under-discriminate. Few items displayed differential item functioning (DIF) across person factors, and there was no consistent pattern in DIF across countries. All items had ordered response categories. Conclusions: The HLS19-COM-P instrument was well accepted in nine countries, in different data collection modes, and could be used to measure COM-HL.

Validating the Volleyball Common Content Knowledge Test

The purpose of this study was to create a valid and reliable volleyball common content knowledge (VB-CCK) test in secondary physical education contexts in the United States. Two physical education teacher educators served as content experts and developed test items for the VB-CCK test. We then established content validity with a group of inservice teachers and determined face validity with preservice teachers. The Rasch model was used in data analysis. The standardized residual contrasts for the items loaded in the range of -.4 to .4, confirming the test was unidimensional and measured VB-CCK. Both infit mean-square residuals and outfit mean-square residuals were within the criterion range of .5 to 1.5 (infit = .8 to 1.1; outfit = .8 to 1.5), which showed the range of the question difficulties matched the respondents’ knowledge levels. The item separation index was 3.46 (reliability = .92; an excellent level) and the person separation index was 1.55 (reliability = .71; an acceptable level). The results provided evidence of the range of question difficulties and respondents’ knowledge levels. The Wright Map added additional evidence that the 40 questions were well distributed from easy to difficult levels and could discriminate different knowledge levels of preservice teachers’ VB-CCK. The study was successful in developing a valid and reliable instrument for PETE programs to assess secondary VB-CCK of their preservice teachers. We propose future CCK studies for both elementary content and secondary content.