Absence Of Differential Item Functioning Research Articles

Differential Item Functioning via Robust Scaling.

This paper proposes a method for assessing differential item functioning (DIF) in item response theory (IRT) models. The method does not require pre-specification of anchor items, which is its main virtue. It is developed in two main steps: first by showing how DIF can be re-formulated as a problem of outlier detection in IRT-based scaling and then tackling the latter using methods from robust statistics. The proposal is a redescending M-estimator of IRT scaling parameters that is tuned to flag items with DIF at the desired asymptotic type I error rate. Theoretical results describe the efficiency of the estimator in the absence of DIF and its robustness in the presence of DIF. Simulation studies show that the proposed method compares favorably to currently available approaches for DIF detection, and a real data example illustrates its application in a research context where pre-specification of anchor items is infeasible. The focus of the paper is the two-parameter logistic model in two independent groups, with extensions to other settings considered in the conclusion.

Item Response Theory Validation of the Forgotten Joint Score for Persons Undergoing Total Knee Replacement.

The Forgotten Joint Score (FJS), a commonly used patient-reported outcome measure, was developed without fully confirming assumptions such as unidimensionality (all items reflect 1 underlying factor), appropriate weighting of each item in scoring, absence of differential item functioning (in which different groups, e.g., men and women, respond differently), local dependence (pairs of items are measuring only 1 underlying factor), and monotonicity (persons with higher function have a higher score). We applied item response theory (IRT) to perform validation of the FJS according to contemporary standards, and thus support its ongoing use. We aimed to confirm that the FJS reflects a single latent trait. In addition, we aimed to determine whether an IRT model could be fitted to the FJS. Participants undergoing primary total knee replacement provided responses to the FJS items preoperatively and at 6 and 12 months postoperatively. An exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and Mokken analysis were conducted. A graded response model (GRM) was fitted to the data. A total of 1,774 patient responses were analyzed. EFA indicated a 1-factor model (all 12 items reflecting 1 underlying trait). CFA demonstrated an excellent model fit. Items did not have equal weighting. The FJS demonstrated good monotonicity and no differential item functioning by sex, age, or body mass index. GRM parameters are reported in this paper. The FJS meets key validity assumptions, supporting its use in clinical practice and research. The IRT-adapted FJS has potential advantages over the traditional FJS: it provides continuous measurements with finer granularity between health states, includes individual measurement error, and can compute scores despite more missing data (with only 1 response required to estimate a score). It can be applied retrospectively to existing data sets or used to deliver individualized computerized adaptive tests. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Measuring Oral Reading Fluency (ORF) Computer-Based and Paper-Based: Examining the Mode Effect in Reading Accuracy and Reading Fluency

Internationally, teachers use oral reading fluency (ORF) measurements to monitor learning progress in reading and adapt instruction to the individual needs of students. In ORF measures, the child reads aloud single syllables, words, or short passages, and the teacher rates in parallel at which items the child makes a mistake. Since administering paper-based ORF requires increased effort on the part of teachers, computer-based test administration is available. However, there are still concerns about the comparability of paper-based and computer-based test modes. In our study, we examine mode effects between paper-based and computer-based test scores for both reading speed and reading accuracy using a German-language ORF assessment for progress monitoring. 2nd- and 3rd-year-students (N = 359) with and without special education needs participated in the study. Results show comparable and high reliability (r > 0.76) and no differential item functioning for both test modes. Furthermore, students showed significantly higher reading speed on the paper-based test, while no differences were found in reading accuracy. In the absence of differential item functioning, we discuss how mean differences can be accounted for, how teachers can be trained to use the different test modes, and how computer-based tests can be safeguarded in practice.

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.

New Item-response Theory-based Dizziness Impact Measures Were Reliable, Valid, and Efficient

<h3>Research Objectives</h3> Calibrate items from the Dizziness Handicap Inventory (DHI) patient-reported outcome measure (PROM) to create an item response theory (IRT)-based item bank and assess its reliability, validity, and efficiency using computerized adaptive test (CAT) and short form (SF) administration modes. <h3>Design</h3> A retrospective cohort including data from patients assessed for dizziness. <h3>Setting</h3> Outpatient rehabilitation. <h3>Participants</h3> Total cohort consisted of 28,815 adult patients [69% female; mean age (SD) 60 (18)] treated in 976 clinics from 49 states (USA) for either vertigo, brain injury, or neck impairments who responded to all 25 DHI items at intake. <h3>Interventions</h3> Not applicable. <h3>Main Outcome Measures</h3> IRT model assumptions of local independence, unidimensionality, item fit, and absence of differential item functioning (DIF) were evaluated. CAT and SF T-scores (mean=50, SD=10) were assessed for reliability, validity, and administration efficiency. Score known-groups validity was assessed for the ability to discriminate among patient groups by demonstrating expected differing levels of dizziness impact. Floor and ceiling effects were assessed, and responsiveness was evaluated using an effect-size statistic. <h3>Results</h3> Three unidimensional item sets were identified, creating 3 distinct PROMs to assess functional (DF; 13 items), positional (DP; 4 items), and emotional (DE; 6 items) status (higher score=lower impact). Each item fit its IRT model. Reliability estimates were 0.72 to 0.92. Except for DIF by age group for DF and DE, no items were flagged for DIF, with negligible DIF impact. Scores discriminated between patient groups in clinically expected ways. Floor and ceiling effects were acceptable (< 15%) excepting a floor effect for the positional PROM (21.4%). Effect sizes were large (>0.8). A CAT was developed for DF, administering an average of 8.3 items (median=9, range 5 to 10). <h3>Conclusions</h3> The 3 dizziness PROMs demonstrated moderate to high reliability, were valid, highly responsive to change; thus, they are suitable for routine clinical administration. <h3>Author(s) Disclosures</h3> Dr. Kallen consults for Net Health Systems, Inc., that owns the Focus on Therapeutic Outcomes (FOTO) Patient Outcomes system that gathers and manages the data analyzed. The authors have no other conflicts to declare.

Reliability, Validity and Efficiency of an Item Response Theory-based Balance Confidence Patient Reported Outcome Measure

<h3>Research Objectives</h3> To calibrate items from the original 16-item Activities-Specific Balance Confidence (ABC) Scale to create an item response theory (IRT)-based item bank and scoring metric and assess its reliability, validity, and efficiency using computerized adaptive test (CAT) and short form (SF) administration modes. <h3>Design</h3> Retrospective cohort; data from patients assessed for balance impairments. <h3>Setting</h3> Outpatient rehabilitation. <h3>Participants</h3> Cohort of 20,354 adult patients [60% female; mean age (SD) 66 (16)] treated for orthopedic and neurological conditions in 822 clinics (44 states; USA) who completed the ABC Scale at intake. <h3>Interventions</h3> Not applicable. <h3>Main Outcome Measures</h3> An IRT-based patient-reported outcome measure (PROM) was developed based on the original 16 ABC items, examining assumptions of local independence, unidimensionality, item fit, and absence of differential item functioning (DIF). CAT and SF T-scores (mean=50, SD=10) were assessed for reliability, validity, and administrative efficiency. Known-groups validity, floor and ceiling effects and responsiveness were evaluated. <h3>Results</h3> All original 16 items were retained in the model, supporting the ABC Scale's unidimensionality and item-fit. A short form was created selecting 6 items that provided the most statistical information at targeted score levels. Reliability estimates were >= 0.95 for both administration modes. Scores discriminated between patient groups in clinically expected ways. Negligible floor and ceiling effects and no item DIF were observed. Change score effect size was medium (0.58). Simulated CAT scores were generated using an average of 4.7 items (median=4, range 4 to 10) and correlated highly with scores derived from the full bank (r=0.99). <h3>Conclusions</h3> The IRT-based balance confidence PROM was reliable, valid, moderately responsive to change, and efficient, with excellent score coverage. The presentation will address optimizing the use of the CAT, SF, and the full ABC Scale, depending on clinical and research purposes. <h3>Author(s) Disclosures</h3> Dr. Kallen consults for Net Health Systems, Inc., the company that owns the Focus on Therapeutic Outcomes (FOTO) Patient Outcomes system that gathers and manages the data analyzed in this manuscript. Dr. Myers is the developer of the ABC Scale. The authors have no other conflicts to declare.

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.

Differential item functioning to validate setting of delivery compatibility in PROMIS-global health.

Patient-reported outcomes measures (PROMs) such as PROMIS are increasingly utilized in healthcare to assess patient perception and functional status, but the effect of delivery setting remains to be fully investigated. To our knowledge, no current study establishes the absence of differential item functioning (DIF) across delivery setting for these PROMIS- Global Health (PROMIS-GH) measures among orthopedic patients. We sought to investigate the correlation of PROMIS-GH scores across in-clinic versus remote delivery by evaluating DIF within the Global Physical Health (GPH) and Global Mental Health (GMH) items. We hypothesize that the setting of delivery of the GPH and GMH domains of PROMIS-GH will not impact the results of the measure, allowing direct comparison between the two delivery settings. Five thousand and seven hundred and eighty-five complete PROMIS-Global Health measures were analyzed retrospectively using the 'Lordif' package on the R platform. DIF was measured for GPH and GMH domains across setting of response (in-clinic vs remote) during the pre-operative period, immediate post-operative period, and 1-year post-operative period using Monte Carlo estimation. McFadden pseudo-R2 thresholds (> 0.02) were used to assess the magnitude of DIF for individual PROMIS items. No GPH or GMH items contained in the PROMIS-GH instrument yielded DIF across in-clinic vs remote delivery setting during the pre-operative, immediate post-operative, or 1-year post-operative window. The GPH and GMH domains within the PROMIS-GH instrument may be delivered in the clinic or remotely with comparable accuracy. This cross-delivery setting validation analysis may aid to improve the quality of patient care by allowing mixed platform PROMIS-GH data tailored to individual patient circumstance.

Assessment of differential item functioning across English and Spanish versions of the Orofacial Esthetic Scale.

To investigate differential item functioning across the Spanish and English versions of the Orofacial Esthetic Scale (OES). OES data were collected from a consecutive sample of a total of 622 adult dental patients (311 English- and 311 Spanish-speaking adults) from HealthPartners dental clinics in Minnesota. We inspected boundary characteristic curves (BCCs) based on item response theory (IRT) in English speakers and Spanish speakers to examine differential item functioning (DIF). Using the Samejima's graded response model, we used the item response theory log-likelihood ratio (IRTLR) approach to test whether DIF was statistically significant. Inspection of the BCCs did not reveal substantial differences in item difficulty and discrimination between English speakers and Spanish speakers. When IRTLR tests were performed for the seven OES items, no item was flagged with significant DIF after P-values were adjusted for multiple comparisons. Pooling of Orofacial Esthetic Scale (OES) data from English and Spanish-speaking dental patients for analysis and interpretation is supported by the absence of differential item functioning (DIF) across the two language groups.

Comparing Performance of Different Equating Methods in Presence and Absence of DIF Items in Anchor Test

This study aims to compare the performance of different small sample equating methods in the presence and absence of differential item functioning (DIF) in common items. In this research, Tucker linear equating, Levine linear equating, unsmoothed and presmoothed (C=4) chained equipercentile equating, and simplified circle arc equating methods were considered. The data used in this study is 8th-grade mathematics test item responses which obtained from Trends in International Mathematics and Science Study (TIMSS) 2015 Turkey sample. Item responses from Booklet-1 (N=199) and Booklet-14 (N=224) are chosen for this study. Data analyses were completed in four steps. In the first step, assumptions for DIF detection and test equating methods were checked. In the second step, DIF analyses were conducted with Mantel Haenszel and logistic regression methods. In the third step, Booklet 1 was chosen as base form and Booklet 14 chosen as a new form, then test equating was conducted under common item nonequivalent groups design. Test equating was done in two phases: the presence and absence of DIF items in the common items. Equating results were evaluated based on standard error of equating (se), bias and RMSE indexes. DIF analyses showed that there were two sizeable DIF items in anchor test. Equating results showed that performances of equating methods are similar in presence and absence of DIF items from anchor test and there is no notable change in se, bias and RMSE values. While the circle arc equating method outperformed other equating methods based on se, 4-moment presmoothed chained equipercentile equating method outperformed other methods based on bias and RMSE evaluation criteria.

The Latin American version of the internalized stigma of mental illness scale (LA-ISMI): a multicentric validation study from three Latin American countries

BackgroundTo date, no data have been available concerning the psychometric characteristics of the Internalized Stigma of Mental Illness scale (ISMI-29) in Latin American countries. The aim of this study was to validate a Latin American version of the ISMI in people with schizophrenia.MethodsThe study included 253 stabilized outpatients with schizophrenia from 3 Mental Health Services in three Latin American countries: Bolivia (N = 83), Chile (N = 85) and Peru (N = 85). We analyzed the psychometric properties using item response and classical test theories. An item reduction was then performed to improve the psychometric properties of the ISMI-29. The final version of the ISMI was tested for construct validity, reliability, external validity and differential item functioning (DIF).ResultsThe five-factor structure of the ISMI-29 was not confirmed using confirmatory factor analysis (RMSEA = 0.12, CFI = 0.77, and WRMR = 2.20). Seventeen items were discarded to obtain a satisfactory psychometric version. The ISMI-12 evaluates 3 dimensions: social stigma (4 items), stigma experience (4), and self-stigma (3). The factor structure accounted for 68% of the total variance. Internal consistency was satisfactory. The scalability was satisfactory, with INFIT statistics within an acceptable range. In addition, the results confirmed the absence of DIF and supported the invariance of the item calibrations between countries.ConclusionThe ISMI-29 is not valid in our sample and should not be used in Latin American countries. The ISMI-12 is the first internalized stigma questionnaire with satisfactory psychometric properties available in Latin American countries. Its brevity could facilitate its dissemination and use in clinical settings.

Reliability and validity of the Basic Depression Questionnaire

Background/ObjectiveDepressive disorders have a high prevalence around the world. They present a great comorbidity with other disorders like anxiety, thereby making a differential diagnosis very difficult. The Basic Depression Questionnaire was designed to palliate this issue by isolating specific depression symptoms. Our aim is to study the reliability, factorial structure, and differential item functioning of this questionnaire. Method: The sample consisted of 1,397 adults without psychological problems (Mage=29.76, SD=11.25, 64.78% women) who completed the CBD. Results: We observed that none of the items presented differential functioning. A monofactorial structure was established. In this model a good fit was obtained by confirmatory factor analysis and a strict invariance by sex. The ordinal alpha was used to check the reliability and it fetched an index of .95. Conclusions: The Basic Depression Questionnaire has adequate psychometric properties. The absence of differential item functioning and the invariance by sex are guarantees of an adequate use to diagnose depression for men and women. So, its clinical use can help to differentiate between the specific diagnoses for depressive disorders and anxiety disorders.

Dyspnea in Amyotrophic Lateral Sclerosis: Rasch-Based Development and Validation of a Patient-Reported Outcome (DALS-15)

ContextDyspnea is a cardinal but often underestimated symptom in amyotrophic lateral sclerosis (ALS). The lack of a satisfying assessment tool leads to diagnostic uncertainty and bears the risk that established life-prolonging and symptom-relieving therapeutic options will not be adequately applied. ObjectivesThe objective of this study was to develop and validate a German language disease-specific patient-reported outcome measure to assess dyspnea in ALS by combination of a qualitative and quantitative approach using Rasch analysis. MethodsBased on input from clinical experts and patients, a preliminary 35-item questionnaire was developed and completed by 94 patients with ALS having dyspnea. Data were subjected to Rasch analysis and tested for required measurement issues such as appropriate response categories, the absence of differential item functioning, local independence, and unidimensionality. ResultsAfter iterative Rasch analyses, the final 15-item Dyspnea-ALS-Scale (DALS-15) was obtained. The scale satisfies the axioms of the Rasch model with good fit statistics, the absence of local dependency, and differential item functioning as well as acceptable unidimensionality. The DALS-15 is optimally targeted and suitable for group and individual use. It shows excellent test-retest reliability and convergent validity. ConclusionThe DALS-15 satisfies strictest modern measurement criteria and has interval scale properties. It fills an important gap in assessment and could be most helpful to optimize symptom management in patients with ALS.

Development of a Work Climate Scale in Emergency Health Services.

An adequate work climate fosters productivity in organizations and increases employee satisfaction. Workers in emergency health services (EHS) have an extremely high degree of responsibility and consequent stress. Therefore, it is essential to foster a good work climate in this context. Despite this, scales with a full study of their psychometric properties (i.e., validity evidence based on test content, internal structure and relations to other variables, and reliability) are not available to measure work climate in EHS specifically. For this reason, our objective was to develop a scale to measure the quality of work climates in EHS. We carried out three studies. In Study 1, we used a mixed-method approach to identify the latent conceptual structure of the construct work climate. Thus, we integrated the results found in (a) a previous study, where a content analysis of seven in-depth interviews obtained from EHS professionals in two hospitals in Gibraltar Countryside County was carried out; and (b) the factor analysis of the responses given by 113 EHS professionals from these same centers to 18 items that measured the work climate in health organizations. As a result, we obtained 56 items grouped into four factors (work satisfaction, productivity/achievement of aims, interpersonal relationships, and performance at work). In Study 2, we presented validity evidence based on test content through experts' judgment. Fourteen experts from the methodology and health fields evaluated the representativeness, utility, and feasibility of each of the 56 items with respect to their factor (theoretical dimension). Forty items met the inclusion criterion, which was to obtain an Osterlind index value greater than or equal to 0.5 in the three aspects assessed. In Study 3, 201 EHS professionals from the same centers completed the resulting 40-item scale. This new instrument produced validity evidence based on the internal structure in a second-order factor model with four components (RMSEA = 0.079, GFI = 0.97, AGFI = 0.97, CFI = 0.97; NFI = 0.95, and NNFI = 0.97); absence of Differential Item Functioning (DIF) in 80% of the items; reliability (α = 0.96); and validity evidence based on relations to other variables, specifically the test-criterion relationship (ρ = 0.680). Finally, we discuss further developments of the instrument and its possible implications for EHS workers.

The Graded and Redefined Assessment of Strength, Sensibility, and Prehension Version 2 Provides Interval Measure Properties.

The Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) is a valid, reliable, and responsive outcome measure to evaluate upper limb function in individuals with tetraplegia. GRASSP generates ordinal total scores; therefore, applicability as an interval level measurement requires testing of its measurement properties. This study examined the metric characteristics with Rasch Analysis to derive interval level scales of the respective GRASSP subtests. The GRASSP was recorded within 10 days, and at 1, 3, 6, and 12 months after cervical spinal cord injury (SCI). Rasch analysis was performed for each GRASSP subscale to assess the following metric assumptions: absence of local item dependency (LID), unidimensionality, monotonicity, item and model fit, reliability, and absence of differential item functioning (DIF) for side (left and right) and examination stage. If these assumptions could not be met, adjustments were undertaken to achieve a good fit to the Rasch model. Seventy-seven individuals with cervical SCI were included (n = 154 arms). Stacking the data for the side (left and right) resulted in a total of 614 observations, which were based on the repeated measurements. With minor adjustments, the GRASSP subscales showed good reliability, item fit, and ordered response options. Local item dependencies were found in the strength and sensibility subscales. Redundancies among some measurement items allowed shortening of the subscales without reasonable loss of reliability. Absence of DIF for the examination stage supported robustness of the subscales over time. The modified GRASSP, now Version 2, subtest scores can be applied as interval level measurements, and the reduction of items within subscales allows for shorter assessment times in clinical studies without degrading metric properties.

Are There Gender Differences in Emotion Comprehension? Analysis of the Test of Emotion Comprehension

This article examines whether there are gender differences in understanding the emotions evaluated by the Test of Emotion Comprehension (TEC). The TEC provides a global index of emotion comprehension in children 3–11 years of age, which is the sum of the nine components that constitute emotion comprehension: (1) recognition of facial expressions, (2) understanding of external causes of emotions, (3) understanding of desire-based emotions, (4) understanding of belief-based emotions, (5) understanding of the influence of a reminder on present emotional states, (6) understanding of the possibility to regulate emotional states, (7) understanding of the possibility of hiding emotional states, (8) understanding of mixed emotions, and (9) understanding of moral emotions. We used the answers to the TEC given by 172 English girls and 181 boys from 3 to 8 years of age. First, the nine components into which the TEC is subdivided were analysed for differential item functioning (DIF), taking gender as the grouping variable. To evaluate DIF, the Mantel–Haenszel method and logistic regression analysis were used applying the Educational Testing Service DIF classification criteria. The results show that the TEC did not display gender DIF. Second, when absence of DIF had been corroborated, it was analysed for differences between boys and girls in the total TEC score and its components controlling for age. Our data are compatible with the hypothesis of independence between gender and level of comprehension in 8 of the 9 components of the TEC. Several hypotheses are discussed that could explain the differences found between boys and girls in the belief component. Given that the Belief component is basically a false belief task, the differences found seem to support findings in the literature indicating that girls perform better on this task

Development and validation of an instrument to assess job satisfaction in eye‐care personnel

PurposeThe aim was to develop and validate an instrument to measure job satisfaction in eye‐care personnel and assess the job satisfaction of one‐year trained vision technicians in India.MethodsA pilot instrument for assessing job satisfaction was developed, based on a literature review and input from a public health expert panel. Rasch analysis was used to assess psychometric properties and to undertake an iterative item reduction. The instrument was then administered to vision technicians in vision centres of Andhra Pradesh in India. Associations between vision technicians’ job satisfaction and factors such as age, gender and experience were analysed using t‐test and one‐way analysis of variance.ResultsRasch analysis confirmed that the 15‐item job satisfaction in eye‐care personnel (JSEP) was a unidimensional instrument with good fit statistics, measurement precisions and absence of differential item functioning. Overall, vision technicians reported high rates of job satisfaction (0.46 logits). Age, gender and experience were not associated with high job satisfaction score. Item score analysis showed non‐financial incentives, salary and workload were the most important determinants of job satisfaction.ConclusionsThe 15‐item JSEP instrument is a valid instrument for assessing job satisfaction among eye‐care personnel. Overall, vision technicians in India demonstrated high rates of job satisfaction.

Proposing a Parkinson's disease-specific tremor scale from the MDS-UPDRS.

This article proposes an International Parkinson and Movement Disorder Society (MDS)-UPDRS tremor-based scale and describes its measurement properties, with a view to developing an improved scale for assessing tremor in Parkinson's disease (PD). This was a cross-sectional, multicenter study of 435 PD patients. Rasch analysis was performed on the 11 MDS-UPDRS tremor items. Construct validity, precision, and test-retest reliability were also analyzed. After some modifications, which included removal of an item owing to redundancy, the obtained MDS-UPDRS tremor scale showed moderate reliability, unidimensionality, absence of differential item functioning, satisfactory convergent validity with medication, and better precision than the raw sum score. However, the scale displayed a floor effect and a need for more items measuring lower levels of tremor. The MDS-UPDRS tremor scale provides linear scores that can be used to assess tremor in PD in a valid, reliable way. The scale might benefit from modifications and studies that analyze its responsiveness.

Development of a patient-reported outcome measure of tophus burden: the Tophus Impact Questionnaire (TIQ-20)

BackgroundTophus burden is currently measured using physical examination and imaging methods. The aim of this study was to develop a patient-reported outcome (PRO) tool to assess tophus burden in people...

Improving the quality of life of multiple sclerosis patients through coping strategies in routine medical practice.

Multiple sclerosis (MS) has a major impact on quality of life (QoL). Coping strategies which may influence QoL have not been identified. Furthermore, there is no coping scale designed to measure coping in MS patients and concise enough for routine medical practice. We used 46 items and 7 coping dimensions; we successively reduced the minimum number of dimensions through confirmatory factor analysis (CFA) and Rasch modelling. The resulting scale was submitted to psychometric validation via an independent cross-sectional analysis. After administration to 331 MS patients, we eliminated 10 of the 46 initial items; a CFA iterative algorithm identified a positive coping (PC) group and a negative coping (NC) group; an iterative reduction algorithm led to a final 10 items questionnaire, which was tested in an independent, new cross-sectional sample of 457 patients. Psychometric tests, including the Rasch model and CFA, successfully validated the scale, confirming the two dimensions and the absence of differential item functioning. The correlation between coping and QoL increased to 0.59 and 0.62 for NC and PC, respectively, compared with 0.33 found with existing scales. Our findings justify a one-dimensional overall coping scale (PC+NC). The effect of coping on QoL can be evaluated simply by adding together a positive and a negative coping strategy, for which we developed a short 10-item scale, which can be considered as an effective means of measuring the impact of coping on QoL and is ideal in routine medical practice.