Interval Scale Measurement Research Articles

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.

Screening for depressive symptoms in adolescence: A Rasch analysis of the short-form childhood depression inventory-2 (CDI 2:SR[S

BackgroundScreening for depressive symptoms during adolescence is of high clinical significance. The shorter 12-item version of the Children's Depression Inventory (CDI 2:SR[S]) was specifically developed for this purpose. Evaluations of the CDI 2:SR[S] psychometrics are limited, however. The purpose of this study was to validate the CDI 2: SR[S] for use as a screening measure using Rasch analysis. MethodsThe CDI 2: SR[S] was administered online to 1513 10–17 year old Western Australian adolescents (635 males, 878 females) from 11 schools. Overall fit, individual item fit, local response dependence, dimensionality, operation of response categories, and differential item functioning (DIF) were examined. ResultsThe Rasch analysis demonstrated the CDI 2: SR[S] has good reliability. Thresholds for all items were ordered, showing its three response categories functioned as intended. One item (I have to push myself to do schoolwork) showed misfit. No items were locally dependent. Two items (I am sad) and (I have to push myself to do schoolwork) showed DIF for gender. At the same level of depression, females reported being sad more than males, while males pushed themselves more to do schoolwork than did females. Adolescents (14–17 years) reported significantly higher mean depressive symptom scores than early adolescents (10–13 years). LimitationsSole reliance on adolescent's self-report and limited data about cultural backgrounds are limitations. ConclusionsThe results support the interval scale measurement properties of the CDI 2: SR[S] and provides educators, clinicians and researchers with a screening measure to assess depressive symptoms in adolescents.

Pengaruh Kompetensi (Hard skill) Dan Pelatihan Terhadap Kinerja Pelaksana Teknis Melalui Kepuasan Kerja Sebagai Variabel Intervening (Studi Pada Pelaksana Teknis Dinas PUPR Kabupaten Serang)

The purpose of this study is to examine and analyze the elements that influence the performance of technical implementers with the effectiveness of competence (hard skills) and the suitability of training through job satisfaction. This research was conducted at the Department of Public Works and Spatial Planning, Serang Regency, using a descriptive quantitative method using a sample of 120 respondents with an interval scale measurement of 1-10 and analyzed using the Smart PLS 3.29 method. The results of this study state that competence (hard skills) has a significant positive effect on employee performance (technical implementers) with a coefficient value of 10%, training has a significant positive effect on employee performance (technical implementers) with a coefficient value of 22.2%, competence (hard skills) has a significant positive effect. on job satisfaction with a coefficient of 20.6%, training has a significant positive effect on job satisfaction with a coefficient of 44.8% and job satisfaction has a significant positive effect on employee performance (technical implementers) with a coefficient value of 65.5%.

Loneliness in adolescence: a Rasch analysis of the Perth A-loneness scale.

The psychometric properties of the Perth A-loneness Scale (PALs) have been extensively validated using classical test theory, but to date no studies have applied a Rasch analysis. The purpose of this study was to validate the PALs four subscales, using Rasch analysis. Responses from 1484 adolescents (58% female, mean age = 12.8years), 131 of whom had a diagnosed neurodevelopmental disorder, from 10 Western Australian secondary schools were included in the Rasch analysis. Overall fit, individual item fit, local response dependence, dimensionality, operation of response categories, and differential item functioning (DIF) were examined. The Rasch analysis supported the factor structure of the PALs. A reasonable to high reliability was obtained for each of the subscales. Participants did not distinguish consistently between the higher categories 'very often' and 'always' on three of the subscales. No item showed Differential Item Functioning (DIF) for neurodevelopmental disorder status and age. One item on each of the Positive and Negative Attitude to Aloneness subscales showed DIF for gender. The results support the interval scale measurement properties of the PALs and provide clinicians and researchers with a measure to assess adolescent loneliness, a construct strongly associated with a constellation of mental health problems.

The Spinal Cord Injury Pressure Ulcer Scale (SCIPUS): an assessment of validity using Rasch analysis.

Secondary analysis of retrospective data. The aim of this study was to further validate the Spinal Cord Injury Pressure Ulcer Scale (SCIPUS) using Rasch analysis. Two rehabilitation centers in Canada. Data were collected as part of the Spinal Cord Injury Knowledge Mobilization Network (SCI KMN) initiative. The SCIPUS was completed within 72 h of inpatient admission. Persons admitted for initial rehabilitation in two inpatient spinal cord rehabilitation programs were included in the project. Data from 886 participants were analyzed, approximately 60% of whom were males. Rasch analyses demonstrated that the SCIPUS, in its current format did not meet criteria required for true measurement. A transformed version of the SCIPUS obtained by deletion of misfitting items and modification of the response scales improved fit to the model and showed preliminary evidence of unidimensionality. The person separation index, however indicated that the scale requires further adjustments of its scoring options. In its original form, the SCIPUS does not meet the requirements of the Rasch model and its total score should be used cautiously. However, following some adjustments to the items such as addressing DIF between sites to insure a standardized assessment across sites and adding response options to some of the items, interval-scale measurement should be possible.

Using patch-based image synthesis to measure perceptual texture similarity

The perceptual similarity of textures has gained considerable attention in the computer vision and graphics communities. Here, we focus on the challenging task of estimating the mutual perceptual similarity between two textures from materials on a consistent scale. Unlike previous studies that more or less directly queried pairwise similarity from human subjects, we propose an indirect approach that is inspired by the notion of just-noticeable differences (JND). Similar metrics are common in imaging and color science, but so far have not been directly transferred to textures, since they require the generation of intermediate stimuli. Using patch-based statistical texture synthesis, we produce continuous transitions between pairs of textures. In a user experiment, participants are then asked to locate an interpolated specimen in the linear continuum. Our intuition is that the JND, defined as the uncertainty with which participants perform this task, is closely related with the perceived pairwise texture similarity. Using a dataset of fabric textures, we show that this metric is particularly suitable to address fine-grained similarities, produces approximately interval-scale measurements and is additionally convenient for crowdsourcing. We further validate our approach by comparing it with a well-established data collection technique using the same dataset.

Measurement Properties of the Interdisciplinary Education Perception Scale in an Australian Allied Health Student Cohort

PurposeMeasurement of interprofessional practice perceptions of students is commonplace in the health professions education literature. There are a range of questionnaires available for researchers to use however the psychometric properties of these vary substantially. The Interdisciplinary Education Perception Scale (IEPS) has been widely used and multiple researchers have published alternative factor structures. The present study sought to build on this work by evaluating the psychometric properties of the IEPS using Rasch analysis. MethodThree-hundred and nineteen students in two Australian osteopathy programs completed the IEPS as part of a larger project into interprofessional education. The measurement properties of the questionnaire were evaluated using Rasch analysis and reliability estimations were also generated for the IEPS. ResultsFit to the Rasch model was achieved by modifying the original 18 item scale, however this was not unidimensional. Subsequent analysis using an alternative factor structure from the literature achieved Rasch model fit and was unidimensional. The final model produced an eight item version of the IEPS (IEPS8) with appropriate psychometric properties, including the ability to create a valid total score. DiscussionThe questionnaire developed as a result of the Rasch analysis provides researchers with a short, psychometrically sound measure of perceptions of their own profession and how their profession works with others. The results also provide an opportunity to explore perceptions pre-post intervention IPE interventions using an interval-scale measure compared to an ordinal one. Researchers are encouraged to utilise this version of the IEPS in future research as it has the potential to be able to discriminate between levels of perception of their own profession and how their profession works with others.

PENGARUH KOMPENSASI FINANSIAL DAN PENGEMBANGAN KARIR TERHADAP TURNOVER INTENTION DENGAN KEPUASAN KERJA SEBAGAI VARIABEL INTERVENING (STUDI PADA KARYAWAN HUMAN RESOURCE

This study aims to determine the effect of financial compensation and career development on turnover intention with job satisfaction as intervening variable. In this research the method used is descriptive and causal method. Data collection techniques used questionnaires with interval scale measurements. Using a saturated sample and obtained 30 respondents using quantitative data analysis methods. From result of calculation of SPSS v.20, result of research with significance level of 0,05% got conclusion: (1) financial compensation have positive and significant effect to job satisfaction obtained t count > t table (5,303 > 1,701) with sig value t table (2.118 > 1.701) with sig 0.05 (0.107 > 0.05) (4) career development has a negative and significant influence on intention turnover obtained –t count > -t table (-2.094 > -1701) with value sig -t table (-2.439 > -1.701) (6) job satisfaction does not mediate compensation relationship (7) job satisfaction does not mediate the career development relationship to turnover intention and the effect is not significantly obtained -t count < -t table (-1.189 < -1.701)

MODIFIED PATH METHODOLOGY FOR OBTAINING INTERVAL-SCALED POSTURAL ASSESSMENTS OF FARMWORKERS.

Agricultural workers perform tasks that frequently require awkward and extreme postures that are associated with musculoskeletal disorders (MSDs). The PATH (Posture, Activity, Tools, Handling) system currently provides a sound methodology for quantifying workers' exposure to these awkward postures on an ordinal scale of measurement, which places restrictions on the choice of analytic methods. This study reports a modification of the PATH methodology that instead captures these postures as degrees of flexion, an interval-scaled measurement. Rather than making live observations in the field, as in PATH, the postural assessments were performed on photographs using ImageJ photo analysis software. Capturing the postures in photographs permitted more careful measurement of the degrees of flexion. The current PATH methodology requires that the observer in the field be trained in the use of PATH, whereas the single photographer used in this modification requires only sufficient training to maintain the proper camera angle. Ultimately, these interval-scale measurements could be combined with other quantitative measures, such as those produced by electromyograms (EMGs), to provide more sophisticated estimates of future risk for MSDs. Further, these data can provide a baseline from which the effects of interventions designed to reduce hazardous postures can be calculated with greater precision.

Public Perception of the Role of Facebook Usage in Political Campaign in Nigeria

NOTE: THIS ARTICLE WAS PUBLISHED WITH THE INFORMING SCIENCE INSTITUTE. Aim/Purpose................................................................................................................................................................................................ This study investigates the public perception towards Facebook usage in the 2015 political campaigns in Nigeria. Background................................................................................................................................................................................................ The utilization of online networking in political issues has kept on developing in late time, even though it was not at first recognized as a political apparatus, political aspirants and politicians at large have now understood its capability. Hence, it has turned into one of the fundamental platforms for political aspirants to propagate diverse campaign messages to their constituents who have an interest in their political career and aspirations. Methodology................................................................................................................................................................................................ The study made use of descriptive survey design with a questionnaire as the instrument for data collection. Data were analyzed using the 2016 Microsoft Excel statistical package with frequency counts and simple percentages presented in tables and graphs. The hypotheses generated in this study were tested via inferential statistical chi-square analysis at 0.05 level of significant. Contribution................................................................................................................................................................................................ Studies that investigate the public perception of the usage of Facebook in electioneering campaign in Northern Nigeria, notably Taraba State is in its embryonic stage. Therefore, this paper is an extension to such body of knowledge. Findings...................................................................................................................................................................................................... The study demonstrated that Facebook was used in the 2015 senatorial electioneering campaigns in southern Taraba, and this influenced electorate to vote a particular candidate. However, it is the perception of the respondents that there were dysfunctions such as deliberate distortions in the information about opponents, abusive speech, distortion of the facts about personal performance, and misinformation as a strategy for influencing on the Facebook pages of the electorates and candidates. Recommendations for Practitioners........................................................................................................................................................... Reliability (e.g. message must be clear, focused, well conveyed, believable, credible, free from abusive speech and attacking of opponents) should be an essential concept in the posted political messages or promises of politicians so as to draw more fans to themselves. Recommendation for Researchers.............................................................................................................................................................. It should be noted that this study centers on southern Taraba alone, therefore, in order to get a more generalized results, it is pertinent for further research to include other parts of Nigeria. Additionally, a combination of content analysis and interview will be helpful in examining the nature of the abusive words/speeches used on Facebook in the 2015 southern Taraba senatorial electioneering campaign. Impact on Society.......................................................................................................................................................................................... Some of the limitations have to do with the nature of the questionnaires them-selves and the kind of variables and measurement models required. The measurements are perceptions rather than quantitative interval or ratio scale measures taken on the variable. Therefore, future research should adopt quantitative interval or ratio scale measures on the variable in order to obtain scientific results. Future Research............................................................................................................................................................................................. It should be noted that this study centres on southern Taraba alone, therefore, in order to get a more generalizable results, it is pertinent for further research to include other parts of Nigeria.

Measuring safety climate in acute hospitals: Rasch analysis of the safety attitudes questionnaire.

BackgroundThe Safety Attitudes Questionnaire (SAQ) is commonly used to assess staff perception of safety climate within their clinical environment. The psychometric properties of the SAQ have previously been explored with confirmatory factor analysis and found to have some issues with construct validity. This study aimed to extend the psychometric evaluations of the SAQ by using Rasch analysis.MethodsAssessment of internal construct validity included overall fit to the Rasch model (unidimensionality), response formats, targeting, differential item functioning (DIF) and person-separation index (PSI).ResultsA total of 420 nurses completed the SAQ (response rate 60 %). Data showed overall fit to a Rasch model of expected item functioning for interval scale measurement. The questionnaire demonstrated unidimensionality confirming the appropriateness of summing the items in each domain. Score reliabilities were appropriate (internal consistency PSI 0.6–0.8). However, participants were not using the response options on the SAQ in a consistent manner. All domains demonstrated suboptimal targeting and showed compromised score precision towards higher levels of safety climate (substantial ceiling effects).ConclusionThere was general support for the reliability of the SAQ as a measure of safety climate although it may not be able to detect small but clinically important changes in safety climate within an organisation. Further refinement of the SAQ is warranted. This may involve changing the response options and including new items to improve the overall targeting of the scale.Trial registrationThis study was registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12611000332921 (21 March 2011).Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1744-4) contains supplementary material, which is available to authorized users.

A procedure simulating Likert scale item responses

Data collected during a survey by means of a questionnaires are, in general, expressed with references to a Likert type scale, giving rise to non-metric data (ordinal categorical). However most of the statistocal procedures used to analyze survey data (for example FA or SEM) required at list interval scale measures, that may be obtained by using proper scaling procedures. In order to compare by simulation, the quantification thecniques most commonly used in the literature we consider necessary to achieve in advance an appropriate algorithm that best reproduces the discretization process followed by the respondents to the Likert questionnaire items. Accordingly, we propose a discretization procedures that, starting from a continuous random variables, describing all possible individual responses to a given stimulus, generates the corresponding categories, chosen among finite sets of integer values.

Verifying Validity of the Household Dietary Diversity Score

The Household Dietary Diversity Score (HDDS) was developed to measure household food access, one of the levels of food security. Previous research has shown dietary diversity is related to food security. However, the validity of the HDDS in the form developed by the Food and Nutrition Technical Assistance (FANTA) project-12 food groups, 24-hour recall-and most frequently used by development organizations and nongovernmental organizations has never been verified. To verify the construct validity of the HDDS. A Rasch model was used to test the extent to which the HDDS meets the criteria required for interval scale measurement, using data from 1015 households in Colombia and Ecuador. Different dietary patterns between Colombia and Ecuador and 2 cultural groups within Ecuador required data to be split into 3 subgroups. For each subgroup, the food groups meeting the criteria and their difficulty ranking were different. Refined indices, containing only those food groups meeting the criteria, contained 7 items in Colombia, 10 for Kichwa households in Ecuador, and 9 for migrant households. The indicator in its current form does not meet all criteria. Even when analyzing culturally homogenous subgroups within a small region, the components of the indicator do not form a reliable way of measuring household-level food access.

Urban Scale Shifts since the Bronze Age: Upsweeps, Collapses, and Semiperipheral Development

This is a study of the growth and decline of cities for the purpose of identifying those events in which they significantly increased in size. Significant changes in the scale of cities are important for understanding the long-term trend toward more complex and hierarchical human societies. We report the results of an inventory of cycles, upsweeps, and collapses of settlements in five separate interpolity systems. Upsweeps are instances in which the largest settlement in a world system significantly increases in size. Collapses occur when the size of the largest settlement greatly decreases and stays down for a significant period of time rather than rebounding. We use regional interpolity systems (world systems) rather than single polities or settlements as our unit of analysis. Because the accurate designation of sweeps requires interval scale measures, we are limited to those regions and time periods for which quantitative estimates of largest settlement sizes are regularly available. We find a total of 18 upsweeps and five downsweeps, and only two instances of prolonged systemwide settlement collapse. We also investigate whether or not the rate of cycles has increased over the long run, and we find that cycles of city growth and decline have not accelerated. We also find a greater rate of urban cycles in the Western (Central) System than in the East Asian System, which supports the usual notion that the Western city system was less stable than the Eastern city system.

Reliability of Musculoskeletal Fitness Tests and Movement Control Impairment Test Battery in Female Health-Care Personnel with Re-Current Low Back Pain

Background: Low back pain (LBP) is one of the most important causes of work absenteeism in health-care personnel. Low performance levels for fitness components, and movement control impairment (MCI) of the spine have been posited to be risk factors for persistent LBP. The aims of this study were to examine the long-term reliability (test I – test II) of selected motor and musculoskeletal fitness tests and the standard MCI test battery in female health-care personnel with nonspecific LBP, and to investigate associations between change in intensity of LBP and variation in test results in two measurement points. Methods: The participants (n=47) were workers in geriatric wards. Long-term reliability of six field tests assessing motor abilities, flexibility and muscular strength, and the MCI test battery were studied. Mean test I – test II time-span was 18 days (SD 7.9). The estimates of reliability for interval-scale measurements (fitness) were typical error (s) of measurement and the coefficient of variation (CV). The reliability of nominal-scale measurements was analysed by the kappa coefficient. Results: The lowest within-subject variation was found in running figure of eight test (s=0.22 s, CV=2.8%) and the highest for modified push-ups (s=1.04 repetitions, CV=12.2%). The kappa values for the dorsal pelvic tilt, sitting knee extension, the anterior pelvic tilt, and lying-prone knee flexion varied between 0.71 and 0.45 but were lower for rocking forwards and backwards (k=0.31) and the one-leg stance (k=0.16). Change in the pain intensity was associated only with variation in test I – test II results for modified push-ups (p=0.045). Conclusions: All of the tests assessing musculoskeletal fitness and four of the MCI tests had an acceptable level of long-term reliability. The two tests for MCI that had poor reliability need to be better standardised in order to serve as reliable clinical measurement tools.

Estimating stocks and flows of nitrogen: Application of dynamic nutrient balance to European agriculture

This study elaborates the dynamic nutrient balance model and applies it to analyze nitrogen use and nitrogen efficiency in agriculture. We use publicly available agricultural production data to estimate the net inflows, stocks and outflows of nitrogen for 14 European countries in years 1961–2009. The dynamic model allows us to analyze the trends in the nitrogen stocks and flows over time, and break down the total outflow of nitrogen into flows to water, air and soil. We argue that the nitrogen outflow, modeled as the decay of nitrogen stock, provides a more reliable and robust agri-environmental indicator than the conventional nutrient balance. Mathematically, the nutrient balance is an interval scale measure, whereas the nitrogen stock and the outflow from stock are ratio scale measures. Nitrogen efficiencies, calculated based on the nitrogen stocks, provide useful and insightful information beyond the conventional eco-efficiency measures defined from the nitrogen balances. The results of this paper can be used as input data for more comprehensive eco-efficiency or productivity analysis and for the evaluation and design of agri-environmental policies in Europe.

A Systematic Literature Review on the Application of Rasch Analysis in Musculoskeletal Disease — A Special Interest Group Report of OMERACT 11

The Rasch measurement model provides robust analysis of the internal construct validity of outcome measures. We reviewed the application of Rasch analysis in musculoskeletal medicine as part of the work leading to discussion in a Special Interest Group in Rasch Analysis at Outcome Measures in Rheumatology 11. A systematic literature review of SCOPUS and MEDLINE was performed (January 1, 1985, to February 29, 2012. Original research reports in English using "Rasch" or "Item Response Theory" in musculoskeletal diseases were assessed by 2 independent reviewers. The topics of focus and analysis methodology details were recorded. Of 212 articles reviewed, 114 were included. The number of publications rose from 1 in 1991-1992 to 23 in 2011-February 2012. Disease areas included rheumatoid arthritis (28%), osteoarthritis (16.6%), and general musculoskeletal disorders (43%). Sixty-six reports (57.9%) evaluated psychometric properties of existing scales and 35 (30.7%) involved development of new scales. Nine articles (7.9%) were on methodology illustration. Four articles were on item banking and computer adaptive testing. A majority of the articles reported fit statistics, while the basic Rasch model assumption (i.e., unidimensionality) was examined in only 57.2% of the articles. An improvement in reporting qualities with Rasch articles was noted over time. In addition, only 11.4% of the articles provided a transformation table for interval scale measurement in clinical practice. The Rasch model has been increasingly used in rheumatology over the last 2 decades in a wide range of applications. The majority of the articles demonstrated reasonable quality of reporting. Improvements in quality of reporting over time were revealed.

Alternating least squares in nonlinear principal components

Principal components analysis (PCA) is probably the most popular descriptive multivariate method for analyzing quantitative data with ratio and interval scale measures. When applying PCA to nominal and ordinal data, the data are processed by a method such as optimal scaling, which nonlinearly transforms nominal and ordinal data into quantitative data. Therefore, PCA with optimal scaling is called nonlinear PCA. Nonlinear PCA reveals nonlinear relationships among variables with different measurement levels and therefore presents a more flexible alternative to ordinary PCA. The alternating least squares algorithm is utilized for nonlinear PCA. The algorithm alternates between optimal scaling for quantifying nominal and ordinal data and ordinary PCA for analyzing optimally scaled data. This article discusses two nonlinear PCA algorithms, namely, PRINCIPALS and PRINCALS. WIREs Comput Stat 2013, 5:456–464. doi: 10.1002/wics.1279This article is categorized under: Algorithms and Computational Methods &gt; Algorithms Statistical and Graphical Methods of Data Analysis &gt; Multivariate Analysis Algorithms and Computational Methods &gt; Numerical Methods Statistical Models &gt; Nonlinear Models Algorithms and Computational Methods &gt; Least Squares

Measurement of social climate within neurobehavioural rehabilitation services using the EssenCES

In forensic mental health settings, quality of social climates is associated with a range of therapeutic assets. An essential characteristic of neurobehavioural rehabilitation services is provision of an enriched environment which reverses contingencies that maintain challenging behaviour. The concept of social climate is therefore equally important to these services. Criticisms of existing measures of social climate led to development of the EssenCES. This was initially validated in German forensic mental hospitals, and subsequently an English translation in equivalent UK services. To determine if EssenCES can be used to measure social climate in neurobehavioural rehabilitation units, responses from 114 staff and patients were analysed using statistical methods from classical test theory. Results were similar to those obtained previously. Rasch analysis was also used to test the assumption that EssenCES comprises a true interval-scale measurement tool. Item–person misfit, erratic responding, redundant response categories and disordered thresholds undermined this assumption. Rating scale recalibration, item reduction, and removing respondents who continued to demonstrate poor fit resulted in a measure with good internal construct validity but questionable external construct validity. Relative merits of modifying EssenCES for use with patients with cognitive impairment versus designing a measure conceptualised for use in neurobehavioural rehabilitation services are discussed.

Further validation of the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) in the UK veterinary profession: Rasch analysis

To examine the psychometric properties of the 14-item Warwick-Edinburgh Mental Well-being Scale (WEMWBS) in the UK veterinary profession by the application of Rasch analysis, and to assess the external construct validity of the derived interval scale measurements. Data sets were derived from two independent cross-sectional surveys of the veterinary profession (n = 8,829 and n = 1,796). Rasch analysis (n = 500) included response option thresholds ordering, tests of fit, differential item functioning, targeting, response dependency, and person separation index (PSI). Unidimensionality was evaluated by principal component analysis of residuals. The findings were validated across further subsamples from both data sets. The external construct validity of the Rasch-fitting item set was evaluated by associations with other measures of psychological health or psychosocial work characteristics. Data for the original 14 items deviated significantly from Rasch model expectations (chi-square = 558.2, df = 112, P = <0.001, PSI = 0.918). A unidimensional 7-item scale (Short WEMWBS, SWEMWBS) with acceptable fit to the model (chi-square = 58.8, df = 56, P = 0.104, PSI = 0.832) was derived by sequential removal of the most misfitting items. The external construct validity of SWEMWBS was supported. SWEMWBS has robust interval-level measurement properties which support its suitability as an indicator of population mental health and well-being in this occupational group with elevated suicide risk.