Work Disability Functional Assessment Battery Research Articles

The role of physical and cognitive/emotional functioning in the associations between common health conditions and working

The degree to which functional abilities explain the negative associations between chronic disease and employment is not well understood. If functional limitations play an important role, then increasing access to accommodations and rehabilitation could facilitate employment among people with chronic illness. If not, other barriers related to living with chronic illness may be at play, calling for other interventions. The goal of this study was to 1) assess how health conditions were associated with employment for adults ages 30–69, and 2) test how much of these illness-employment associations was explained by physical and cognitive/emotional functioning. We fielded the state-of-the-art Work Disability Functional Assessment Battery (WD-FAB) in the nationally-representative RAND American Life Panel (N = 1774) in 2020, stratifying the sample by age and educational attainment. We found that mental health conditions, nervous system/sensory conditions, and cardiovascular conditions were significantly associated with large reductions in the probability of working, at −8, −10, and −19 percentage points (pp) respectively, while there were no significant associations for other conditions. Functional abilities were positively associated with employment to different degrees depending on education. Among those without college degrees, physical functioning (+16 pp) but not cognitive/emotional functioning was significantly associated with working. Among those with college degrees, both physical (+6 pp) and cognitive/emotional (+4 pp) functioning were associated with working. Older workers (ages 51–69) showed a larger association between physical functioning and work with no association between cognitive/emotional functioning and work. Importantly, accounting for functioning reduced the negative associations with employment for mental health and nervous system/sensory conditions but not for cardiovascular conditions. This implies that, for the former conditions, accommodating functional limitations could promote greater employment. However, broader accommodations, such as paid sick leave, increased control over work schedules, and other improvements to working conditions may be necessary to reduce work exits due to cardiovascular conditions.

Linking job duties, functioning, and employment status using the Work-Disability Functional Assessment Battery (WD-FAB): An expert coding and quantitative analysis.

An understanding of the link between specific occupational demands and individual worker functioning is limited, although such information could permit an assessment of the fit between the two in a manner that would inform national and state disability programs such as vocational rehabilitation and Social Security disability programs. Our goal was to examine the utility of assessing physical and mental functioning relative to self-reported job duties to identify the domains of worker functioning most likely to create barriers to fulfilling an occupation's specific requirements. Through primary survey data collection, 1770 participants completed the Work-Disability Functional Assessment Battery (WD-FAB) instrument after reporting details on their occupations (or most recent occupation if not working). Expert coders evaluated the level of function expected to successfully carry out each self-reported job duty with respect to six scales of physical and mental function. Quantitative analysis is used to examine the relationship between functioning and job duties. Those not working due to disability were more likely to fall short of the threshold of the physical and mental functioning requirements of their last job's three main job duties compared to those currently employed. Mental function scales were most likely to be the area experiencing a shortfall. Functional difficulties impede the ability to continue working in particular jobs that require that ability. This points to a need for specific accommodations to be implemented to bridge the gap between job requirements and functional capacity so that workers may remain engaged in their current work.

Regularized Bayesian calibration and scoring of the WD-FAB IRT model improves predictive performance over marginal maximum likelihood.

Item response theory (IRT) is the statistical paradigm underlying a dominant family of generative probabilistic models for test responses, used to quantify traits in individuals relative to target populations. The graded response model (GRM) is a particular IRT model that is used for ordered polytomous test responses. Both the development and the application of the GRM and other IRT models require statistical decisions. For formulating these models (calibration), one needs to decide on methodologies for item selection, inference, and regularization. For applying these models (test scoring), one needs to make similar decisions, often prioritizing computational tractability and/or interpretability. In many applications, such as in the Work Disability Functional Assessment Battery (WD-FAB), tractability implies approximating an individual’s score distribution using estimates of mean and variance, and obtaining that score conditional on only point estimates of the calibrated model. In this manuscript, we evaluate the calibration and scoring of models under this common use-case using Bayesian cross-validation. Applied to the WD-FAB responses collected for the National Institutes of Health, we assess the predictive power of implementations of the GRM based on their ability to yield, on validation sets of respondents, ability estimates that are most predictive of patterns of item responses. Our main finding indicates that regularized Bayesian calibration of the GRM outperforms the regularization-free empirical Bayesian procedure of marginal maximum likelihood. We also motivate the use of compactly supported priors in test scoring.

Characteristics of Enrollees in the Supported Employment Demonstration.

The Supported Employment Demonstration (SED), a multiyear (2016-2022), randomized controlled trial funded by the Social Security Administration, recruited a nontraditional sample of benefits applicants with self-reported or documented mental health conditions who were denied disability benefits and who expressed a desire for employment. This study describes the characteristics of the SED sample at baseline. The authors analyzed baseline data from the 2,960 eligible enrollees, including responses to the Composite International Diagnostic Interview, the 12-item Short-Form Health Survey (SF-12), and the Work Disability Functional Assessment Battery (WD-FAB). A majority of SED enrollees self-identified as female (57%), White (56%), and non-Hispanic (87%). Many were 35 years or older (58%), reported at least a high school education (81%), lived with relatives (69%), had never married (55%), were unemployed (81%), and were poor. Median monthly household income was $1,200. Anxiety disorders (71%), personality disorders (65%), and mood disorders (61%) were prevalent. Enrollees reported a mean±SD of 2.5±1.3 mental health conditions and 3.5±2.1 general medical conditions. Health-related quality of life was low, relative to national norms: mean scores for the sample were 32.6±12.5 on the SF-12 mental component summary and 38.3±13.0 on the physical component summary. Mean scores on the WD-FAB subdomains were more than a SD below norms. At baseline, the SED sample had multiple mental health and general medical conditions, low quality of life, and low functional ability. Despite these challenges, the ongoing SED intervention seeks to build on enrollees' expressed desire for employment.

Demographic and functional differences among social security disability claimants.

Sociodemographic characteristics may influence responses on self-reported measures. Differential item functioning (DIF) is when individuals expected to have the same ability level on a construct of interest have a different probability of endorsing an item on an item response theory (IRT) scale due to population characteristics. The goal of this study was to identify DIF for items in an outcome instrument by sociodemographic factors and, one controlling for DIF, assess true differences in function by those same factors. The Work Disability Functional Assessment Battery 2.0 (WD-FAB 2.0) is an IRT-based self-reported measure of activity limitations relevant to work. Two samples from WD-FAB developed were used: 3793 SSA disability claimants randomly drawn from a pool of 16,500 claimants and a general sample if 2100 working age adults. We used a two-step IRT-based DIF method for three pairs of respondent characteristics: age, gender, and race/ethnicity, and calculated the weighted absolute difference between item characteristic curves. Independent two-group T-tests assessed differences in scores across groups. Seventeen items displayed DIF. Men had higher scores than women on two physical and two mental function scales. Older respondents had lower physical and higher mental function scores. The lower education group had lower mental function scores. DIF impacts function measurement and is important when assessing psychometric characteristics of instruments. Self-report measures should include diverse samples to conduct similar analyses. WD-FAB 2.0 scores are now reflections of function with reduced bias related to gender, race/ethnicity, or age.

Psychometric Evaluation of the Improved Work-Disability Functional Assessment Battery

ObjectiveTo assess psychometric properties of the improved Work Disability Functional Assessment Battery (WD-FAB 2.0). DesignLongitudinal study. SettingCommunity. ParticipantsThree samples of working-age (21-66) adults (N=1006): (1) unable to work because of a physical condition (n=375); (2) unable to work because of a mental health condition (n=296); (3) general United States working age sample (n=335). InterventionNA. Main Outcome MeasuresAll samples completed the WD-FAB 2.0; the second administration came 5 days after the first. Construct validity was examined by convergent and divergent correlational analysis using legacy measures. Test-retest reliability was assessed by intraclass correlation coefficients (ICC3,1). Standard error of the mean (SEM) and minimal detectable change (MDC90) were calculated to measure scale precision and sensitivity. ResultsPhysical function ICCs ranged from 0.69 to 0.77 in the general sample, and 0.66 to 0.86 in the disability sample. Mental health function scales ICCs ranged from 0.62 to 0.73 in the general sample, and 0.74 to 0.76 in the disability sample. SEMs for all scales indicated good discrimination; those for the physical function scales were generally lower than those for the mental health scales. MDC90 values ranged from 3.41 to 10.55. Correlations between all WD-FAB 2.0 scales and legacy measures were in the expected direction. ConclusionsThe study provides substantial support for the reliability and construct validity of the WD-FAB 2.0 among 3 diverse samples. Although initially developed for use within the Social Security Administration (SSA), these results suggest that the WD-FAB 2.0 could be used for assessment and measurement of work-related physical and mental health function in other contexts as well.

The Work Disability Functional Assessment Battery (WD-FAB): Development and validation review

Comprehensive, efficient assessment of work-related activity limitations is imperative to government disability programs and clinicians working with patients experiencing work limitations. This article describes the development and initial validation of a newly developed instrument: the Work Disability Functional Assessment Battery (WD-FAB). The WD-FAB characterises physical and mental function across 8 key dimensions related to work: Basic Mobility; Upper Body Function; Fine Motor Function; Community Mobility; Mood & Emotions; Resilience & Sociability; Self-Regulation; and Cognition & Communication. The WD-FAB draws upon a pool of over 300 items to generate scores for all 8 scales in under 15 minutes. WD-FAB scores allow direct comparisons between individuals with self-reported activity limitations and sex- and age-matched adults. Future research with the WD-FAB in both the US and Europe has potential implications for enhancing disability assessment methodologies within the context of disability determination and insurance medicine systems.

The Work Disability Functional Assessment Battery

Leighton Chan (1961) and Julia Porcino (1989) play key roles in developing the Work Disability Functional Assessment Battery (WD-FAB), a new and efficient instrument for the assessment and re-evaluation of work disability based on state-of-the-art methodologies. When they were in Belgium in early March, TBV took the opportunity to learn first-hand about the instrument, its origin, potential, and about the people behind it.

Validation of the Work-Disability Physical Functional Assessment Battery

ObjectiveTo examine the validity of the self-report Work-Disability Functional Assessment Battery (WD-FAB) physical function scales relative to clinician ratings of function and a performance-based functional capacity evaluation called the Physical Work Performance Evaluation (PWPE). DesignCross-sectional. SettingOutpatient rehabilitation. ParticipantsAdults (N=50) participating in physical therapy for musculoskeletal conditions. InterventionsNot applicable. Main Outcome MeasuresPatients completed the PWPE and the WD-FAB physical function scales including Changing and Maintaining Body Position, Whole Body Mobility, Upper Body Function, and Upper Extremity Fine Motor. The physical therapist also answered the WD-FAB questions on the patient’s physical functioning. The WD-FAB computer-adaptive test version administered up to 10 items for each scale. The PWPE produces ratings from 0 to 5 indicating overall Level of Work ability: 0 (unable to work); 1 (sedentary); 2 (light); 3 (medium); 4 (heavy); 5 (very heavy). The PWPE also produces Level of Work ability ratings in the Dynamic Strength, Position Tolerance, and Mobility subsections. ResultsParticipating in the study were 50 patients with 1 or more conditions (shoulder, n=21; knee, n=16; low back, n=13; ankle/foot, n=10; neck, n=8; hip, n=7). The patient-based WD-FAB scores demonstrated moderate, statistically significant correlations with the provider proxy WD-FAB report (R=.49-.65). The WD-FAB Upper Body Function scale scores demonstrated moderate strength relationships with the PWPE overall ratings. The Whole Body Mobility and Changing and Maintaining Body Position scales did not demonstrate statistically significant relationships with the PWPE overall ratings. ConclusionsWe found moderate evidence for validity for the WD-FAB Upper Body Function, Whole Body Mobility, and Changing and Maintaining Body Position scales relative to clinician report and varied evidence relative to the PWPE in this clinical sample.

Updating the Evidence on Functional Capacity Evaluation Methods: A Systematic Review.

Objectives To synthesize the evidence on the psychometrics functional capacity evaluation (FCE) methods. Methods A systematic literature search in nine databases. The resulting articles were screened based on predefined in- and exclusion criteria. Two reviewers independently performed this screening. Included studies were appraised based on their methodological quality. Results The search resulted in 20 eligible studies about nine different FCE methods. The Baltimore Therapeutic Equipment work simulator showed a moderate predictive validity. The Ergo-Kit (EK) showed moderate variability and high inter- and intra-rater reliability. Low discriminative abilities and high convergent validity were found for the EK. Concurrent validity of the EK and the ERGOS Work Simulator was low to moderate. Moderate to high test-retest, inter- and intra-reliability was found in the Isernhagen Work-Systems (IWS) FCE. The predictive validity of the IWS was low. The physical work performance evaluation (PWPE) showed moderate test-retest reliability and moderate to high inter-rater reliability. Low internal and external responsiveness were found for the PWPE, predictive validity was high. The predictive validity of the short-form FCE was also high but need to be further examined on several psychometric properties. Low discriminative and convergent validity were found for the work disability functional assessment battery. The WorkHab showed moderate to high test-retest, inter- and intra-rater reliability. Conclusion Well-known FCE methods have been rigorously studied, but some of the research indicates weaknesses in their reliability and validity. Future research should address how these weaknesses can be overcome.

Improving Assessment of Work Related Mental Health Function Using the Work Disability Functional Assessment Battery (WD-FAB).

Purpose To improve the mental health component of the Work Disability Functional Assessment Battery (WD-FAB), developed for the US Social Security Administration's (SSA) disability determination process. Specifically our goal was to expand the WD-FAB scales of mood & emotions, resilience, social interactions, and behavioral control to improve the depth and breadth of the current scales and expand the content coverage to include aspects of cognition & communication function. Methods Data were collected from a random, stratified sample of 1695 claimants applying for the SSA work disability benefits, and a general population sample of 2025 working age adults. 169 new items were developed to replenish the WD-FAB scales and analyzed using factor analysis and item response theory (IRT) analysis to construct unidimensional scales. We conducted computer adaptive test (CAT) simulations to examine the psychometric properties of the WD-FAB. Results Analyses supported the inclusion of four mental health subdomains: Cognition & Communication (68 items), Self-Regulation (34 items), Resilience & Sociability (29 items) and Mood & Emotions (34 items). All scales yielded acceptable psychometric properties. Conclusions IRT methods were effective in expanding the WD-FAB to assess mental health function. The WD-FAB has the potential to enhance work disability assessment both within the context of the SSA disability programs as well as other clinical and vocational rehabilitation settings.

Improving measures of work-related physical functioning.

To expand content of the physical function domain of the Work Disability Functional Assessment Battery (WD-FAB), developed for the US Social Security Administration's (SSA) disability determination process. Newly developed questions were administered to 3532 recent SSA applicants for work disability benefits and 2025 US adults. Factor analyses and item response theory (IRT) methods were used to calibrate and link the new items to the existing WD-FAB, and computer-adaptive test simulations were conducted. Factor and IRT analyses supported integration of 44 new items into three existing WD-FAB scales and the addition of a new 11-item scale (Community Mobility). The final physical function domain consisting of: Basic Mobility (56 items), Upper Body Function (34 items), Fine Motor Function (45 items), and Community Mobility (11 items) demonstrated acceptable psychometric properties. The WD-FAB offers an important tool for enhancement of work disability determination. The FAB could provide relevant information about work-related functioning for initial assessment of claimants; identifying denied applicants who may benefit from interventions to improve work and health outcomes; enhancing periodic review of work disability beneficiaries; and assessing outcomes for policies, programs and services targeting people with work disability.

Development of a New Instrument to Assess Work-Related Function: Work Disability Functional Assessment Battery (WD-FAB)

Abstract Date Presented 4/10/2016 This research describes the development of the Work Disability Functional Assessment Battery (WD–FAB). The WD–FAB characterizes a person’s functioning along six key dimensions. The WD–FAB may be useful among occupational therapists focusing on work rehabilitation and disability evaluation. Primary Author and Speaker: Elizabeth Marfeo Contributing Authors: Pengsheng Ni, Mark Meterko, Molly Marino, Kara Peterik, Christine McDonough, Elizabeth K. Rasch, Diane Brandt, Leighton Chan, Alan Jette

Work-related measures of physical and behavioral health function: Test-retest reliability

BackgroundThe Work Disability Functional Assessment Battery (WD-FAB), developed for potential use by the US Social Security Administration to assess work-related function, currently consists of five multi-item scales assessing physical function and four multi-item scales assessing behavioral health function; the WD-FAB scales are administered as Computerized Adaptive Tests (CATs). ObjectiveThe goal of this study was to evaluate the test-retest reliability of the WD-FAB Physical Function and Behavioral Health CATs. MethodsWe administered the WD-FAB scales twice, 7–10 days apart, to a sample of 376 working age adults and 316 adults with work-disability. Intraclass correlation coefficients were calculated to measure the consistency of the scores between the two administrations. Standard error of measurement (SEM) and minimal detectable change (MDC90) were also calculated to measure the scales precision and sensitivity. ResultsFor the Physical Function CAT scales, the ICCs ranged from 0.76 to 0.89 in the working age adult sample, and 0.77–0.86 in the sample of adults with work-disability. ICCs for the Behavioral Health CAT scales ranged from 0.66 to 0.70 in the working age adult sample, and 0.77–0.80 in the adults with work-disability. The SEM ranged from 3.25 to 4.55 for the Physical Function scales and 5.27–6.97 for the Behavioral Health function scales. For all scales in both samples, the MDC90 ranged from 7.58 to 16.27. ConclusionBoth the Physical Function and Behavioral Health CATs of the WD-FAB demonstrated good test-retest reliability in adults with work-disability and general adult samples, a critical requirement for assessing work related functioning in disability applicants and in other contexts.

Work Disability Functional Assessment Battery: Feasibility and Psychometric Properties

ObjectiveTo assess the feasibility and psychometric properties of 8 scales covering 2 domains of the newly developed Work Disability Functional Assessment Battery (WD-FAB): physical function (PF) and behavioral health (BH) function. DesignCross-sectional study. SettingCommunity. ParticipantsAdults (N=973) unable to work because of a physical (n=497) or a mental (n=476) disability. InterventionsNot applicable. Main Outcome MeasuresEach disability group responded to a survey consisting of the relevant WD-FAB scales and existing measures of established validity. The WD-FAB scales were evaluated with regard to data quality (score distribution, percentage of “I don't know” responses), efficiency of administration (number of items required to achieve reliability criterion, time required to complete the scale) by computerized adaptive testing (CAT), and measurement accuracy as tested by person fit. Construct validity was assessed by examining both convergent and discriminant correlations between the WD-FAB scales and scores on same-domain and cross-domain established measures. ResultsData quality was good, and CAT efficiency was high across both WD-FAB domains. Measurement accuracy was very good for PF scales; BH scales demonstrated more variability. Construct validity correlations, both convergent and divergent, between all WD-FAB scales and established measures were in the expected direction and range of magnitude. ConclusionsThe data quality, CAT efficiency, person fit, and construct validity of the WD-FAB scales were well supported and suggest that the WD-FAB could be used to assess PF and BH function related to work disability. Variation in scale performance suggests the need for future work on item replenishment and refinement, particularly with regard to the Self-Efficacy scale.

Combining agreement and frequency rating scales to optimize psychometrics in measuring behavioral health functioning

ObjectiveThe goal of this article was to investigate optimal functioning of using frequency vs. agreement rating scales in two subdomains of the newly developed Work Disability Functional Assessment Battery: the Mood & Emotions and Behavioral Control scales. Study Design and SettingA psychometric study comparing rating scale performance embedded in a cross-sectional survey used for developing a new instrument to measure behavioral health functioning among adults applying for disability benefits in the United States was performed. ResultsWithin the sample of 1,017 respondents, the range of response category endorsement was similar for both frequency and agreement item types for both scales. There were fewer missing values in the frequency items than the agreement items. Both frequency and agreement items showed acceptable reliability. The frequency items demonstrated optimal effectiveness around the mean ± 1–2 standard deviation score range; the agreement items performed better at the extreme score ranges. ConclusionFindings suggest an optimal response format requires a mix of both agreement-based and frequency-based items. Frequency items perform better in the normal range of responses, capturing specific behaviors, reactions, or situations that may elicit a specific response. Agreement items do better for those whose scores are more extreme and capture subjective content related to general attitudes, behaviors, or feelings of work-related behavioral health functioning.