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Functional Assessment for Adults with Disabilities (2019)

Chapter: 9 Overall Conclusions

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Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
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9

Overall Conclusions
1

This chapter presents overall conclusions derived from the chapter-specific findings and conclusions detailed throughout the report.

OVERALL CONCLUSIONS

The committee’s chapter-specific findings and conclusions (some of which are highlighted in the next section) served as the basis for the five overall conclusions (see Box 9-1) presented in the following subsections.

Relationship of Functional Abilities to Work Participation

Current models of disability, such as the International Classification of Functioning, Disability and Health (ICF) model, consider disability to involve the effects (limitations) an individual’s health condition places on his or her ability to function and participate fully in society. In keeping with these models, assessment of individuals’ functional abilities relevant to work requirements is an important part of determining whether they are able to meet workplace demands and sustain work performance on a regular and continuing basis.

Numerous validated performance-based and self-report instruments are available to assess physical and mental functions and can be used to inform disability determination. However, as illustrated by the committee’s

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1 This chapter does not include references. Citations to support the text and conclusions herein are provided in previous chapters of the report.

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

conceptual framework (see Figure 2-3 in Chapter 2), it is a challenge to extrapolate from individuals’ ability to perform specific activities and tasks to their ability to perform and sustain full-time work on a regular and continuing basis. Certain physical demands of jobs, such as sitting, standing, walking, lifting, and climbing, may relate more directly than mental/cognitive demands to activities that are amenable to functional assessment. For example, assessment of individuals’ functional abilities with respect to adaptability and work-related personal interactions is more complicated than assessment of whether and how long an individual can sit, stand, or walk. Moving from assessment of individual functional abilities to the ability to perform tasks and meta-tasks as required for work participation creates challenges. Evaluation of the ability to perform a single work activity needs to reflect the context and practical relevance of an individual’s being able to hold a job, taking account of personal and contextual (organizational and environmental) factors that influence individuals’ capability to perform and sustain work. These include factors associated with an individual’s health condition and its treatment that limit the ability to perform sustained work activities on a regular and continuing basis.

For these reasons, the committee drew the following conclusion:

  1. Individuals’ assessed functional abilities relevant to work requirements when assessed outside of actual work settings may be
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

insufficient to establish their capacity to perform full-time work on a regular and continuing basis.

  • Assessment of functional abilities does not necessarily address an individual’s capacity to perform tasks required for work participation. Although an individual may be capable of performing each activity separately, he or she may not be able to coordinate and sequence them effectively.
  • While an individual may be able to perform work tasks successfully during a single assessment, he or she may be unable to perform required work tasks on a sustained or consistent (day-to-day) basis because of one or more underlying physical and/or mental health conditions.
  • It is important to consider that testing is typically administered in a controlled, quiet environment without extraneous noise, social demands, and other factors that typically occur on a job, which, depending on the individual, can adversely affect the ability to perform work tasks.
  • Factors associated with an individual’s health condition (e.g., treatment demands, side effects) may limit the ability to participate in work on a regular and continuing basis even if the person is able to perform each of the tasks associated with a job.
  • Similarly, environmental factors (e.g., physical [built and natural], social, and organizational) may limit an individual’s ability to participate in work on a regular and continuing basis even if the person is able to perform the relevant work requirements.
  • An individual’s capacity to perform work requirements successfully in one specific work environment does not necessarily indicate the ability to perform the same work in a different setting.

Multiple Sources of Work-Related Functional Information

There are a variety of methods for collecting functional information (e.g., diagnostic testing, performance-based measures, self- or proxy-report measures), each of which has strengths and weaknesses, and the results of one are often used to validate those of another. Each method can yield instruments with satisfactory psychometric properties that allow their implementation in disability decision making. Numerous evidence-based self-report and performance-based measures of physical and mental function are available, although they may be limited by a number of factors, including an individual’s underlying physical condition and cognitive status; the experience of pain, depression, or anxiety; and respondent bias or the person’s level of effort. The use of validated instruments or test batteries that include validity measures can help testers determine the validity of the results obtained.

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

Another potential threat to the validity of assessments of functional abilities is use of measures in populations in whom they have not been validated. Self-report and performance measures of physical function provide complementary information, and together can be used to assess an individual’s overall functional status, providing a more complete picture of whether or how well the individual will be able to perform everyday activities, including work, on a sustained basis than can be obtained with either type of measure alone. Third-party sources (e.g., friends and family members, health care and social service professionals, workplace colleagues and employers) who are sufficiently familiar with the applicant’s activities, health, and functional status can be particularly helpful for providing ancillary information on health and behavioral matters, physical and mental functioning, and workplace performance, although such reports are at times influenced by such factors as self-interest, mixed motives, and partial or inaccurate observations. Combining and evaluating the convergence of information from different sources (e.g., self-reports, quantitative measures, medical records, consultative examinations) increases confidence in the validity of the information available for evaluating an individual’s ability to work.

For these reasons, the committee drew the following conclusion:

  1. The validity of the results of work-related functional assessments is enhanced by a comprehensive approach that includes test results and other information about an individual’s physical and mental functional abilities from multiple sources, as well as relevant social and environmental factors and the full scope of tasks involved in a job and sustained gainful employment.
    • No single source of information is likely to provide all of the information needed to evaluate an individual’s ability to work.
    • Professionals in multiple disciplines administer and interpret results of assessments for physical and mental function. Those with responsibility for repeated assessments may render more detailed and accurate evaluations of an individual’s physical and/or mental functioning over time relative to medical specialists who have less frequent interactions with the person and less time per encounter during the same observation period.
    • Convergence of information from multiple sources increases confidence in its validity. It is important to combine and evaluate the consistency of information from different sources (e.g., self-reports, quantitative measures, medical records, consultative examinations) when evaluating an individual’s ability to work.
    • Standardized self-report questionnaires are an important source of information regarding the nature and severity of an applicant’s
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
  • functional limitations, especially when used in conjunction with other assessments.

  • Qualitative data provided by applicants, family members, and other key sources who are sufficiently familiar with the applicant’s activities, health, and functional status, in combination with review of medical evidence, complement quantitative information that serves as the basis for disability decisions.
  • The use of measures based on item response theory that can be administered using computer adaptive testing can decrease respondent burden by reducing survey length and administration time while minimizing measurement error.

Integrated Assessment of Work-Related Functional Ability

Given that measuring function is complex and that work participation is a multidimensional construct, a single physical or mental assessment instrument, by itself, cannot provide a complete assessment of function. While specific assessment instruments measure physical and mental functional abilities at the impairment, body part, or organ system level, “integrated” assessment instruments that provide information regarding the integrated effect of individuals’ impairments on general daily life and participation can capture the additive and sometimes multiplicative effects of multiple impairments and comorbid conditions on individuals’ functional abilities. Several evidence-based instruments and instrument sets are available that provide integrated information about individuals’ overall functional capabilities and limitations and could provide helpful information for determinations of work disability. The most informative evaluations of function may include integrated assessments in addition to specific assessments of body structures and systems.

The Work Disability Functional Assessment Battery (WD-FAB) is a new instrument developed to assess physical and mental functional abilities relevant to work requirements. It may be most useful for understanding self-reported physical function. The Patient-Reported Outcomes Measurement Information System (PROMIS), Quality of Life in Neurological Disorders (Neuro-QoL), and the National Institutes of Health (NIH) Toolbox also may be useful in understanding the functioning of an applicant. Currently, there is no evidence to support drawing direct inferences from the scores of these instruments with respect to employability.

Professionals with responsibility for repeated assessments using standardized assessment tools and procedures may render more detailed and accurate evaluations of an individual’s physical and/or mental functioning over time relative to medical specialists who have less frequent interactions with the person and less time per encounter during the same observation

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

period. Understanding the relationship between chronic illness and functioning is important because some major illnesses are episodic in nature, with severity of symptoms and functional impairments varying over time, and with periods of greater severity ranging from weeks to months.

For these reasons, the committee drew the following conclusion:

  1. Assessments that integrate information about impairments and abilities, including multiple tests of different types, repeated over time, provide the most useful information about work-related function.
    • Numerous validated tests are available for measuring physical and mental functional abilities at the impairment and body or organ system level.
    • No single tool, by itself, can reliably and consistently determine the inability or ability to work.
    • Available instruments, whether based on performance, self-report, or third-party sources, are useful individually, but their value may be increased when different types of instruments are combined to provide a fuller picture of an individual’s ability or inability to sustain work on a regular and continuing basis, especially when they can be repeated over time.
    • Integrated assessment measures are useful for capturing the additive and sometimes multiplicative effects of multiple impairments and comorbid conditions on an individual’s functional ability to meet work requirements.

Challenges for Assessment of Work-Related Functional Abilities

The committee’s conceptual framework for assessing work capacity (see Figure 2-3 in Chapter 2) demonstrates the complexity and challenges of functional assessments, especially the use of instruments that assess only body and structure function or impairment, in moving from individuals’ ability to perform specific activities and tasks to their capacity to perform and sustain full-time work on a regular and continuing basis. In addition, there are a number of threats to the validity of assessments of functional abilities, including testing of maximal versus typical performance, assessment of episodic activity versus sustained task performance, absence of standardized testing conditions, mixed-motive incentives, compromised test integrity owing to prior use of the test in low-stakes testing applications, and diverse test populations on whom tests may not have been validated. Symptoms associated with depression (e.g., fatigue, difficulty concentrating, and slowed response speed) can impair functioning and frequently compound work-related functional limitation in the context of other primary

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

impairments. It is important to collect information about the nature and original purpose of an assessment instrument as well as the conditions and context in which it was administered to help in understanding the results with respect to potential limitations to their generalizability.

For these reasons, the committee drew the following conclusion:

  1. Numerous challenges complicate accurate assessment of an individual’s ability to work, including the following:
    • Measures of physiological, morphological, psychological, or cognitive severity (e.g., laboratory findings, signs, or symptoms of impairments) may not correlate with the severity of functional limitations (i.e., the effect of a condition on an individual’s ability to work or conduct daily life).
    • It is simpler to demonstrate inability or limitation to perform a specific activity (e.g., reaching overhead, climbing a ladder) than to demonstrate an individual’s ability to perform the combination of activities required for different occupations. Tests of functional abilities often do not measure whether an individual is able to combine functions to perform tasks as needed for work.
    • Successful work performance is more than the sum of the specific tasks and skills required, and the overall limitation to successful work for an individual is often more than the sum of single impairments.
    • Threats to the validity of assessments of functional abilities include testing of maximal versus typical performance, assessment of episodic activity versus sustained task performance, absence of standardized testing conditions, mixed-motive incentives, compromised test integrity owing to prior use of the test in low-stakes testing applications, and diverse test populations on whom tests may not have been validated.
    • Symptoms associated with psychological conditions such as depression and anxiety can affect a person’s ability to manage one or more limitations in a work setting. Therefore, it is necessary to consider them when assessing an individual’s ability to sustain work on a regular and continuing basis because a person’s capacity to work may be overestimated if a psychological comorbidity is present.
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

Factors Limiting the Quality and Quantity of Information on Functional Ability for an Applicant

When evaluating the utility of a functional assessment instrument for informing disability determinations, it is important to consider the instrument’s performance across multiple subgroups (e.g., age, gender, socioeconomic status, race, ethnicity, cultural group) as a principle of ethical practice. Numerous instruments are available for assessing physical and mental functions, but not all account for the range of cultural, linguistic, or literacy factors among the population being assessed. Differences in gender, race, ethnicity, and culture can affect individuals’ perceptions of illness and their reporting of health information. Development and validation of patient-reported symptom measures and clinician/observer-rendered assessments vary in the extent to which they have been tested or adapted across diverse racial/ethnic and cultural populations. Cross-cultural adaptations and validations of assessments in different cultural contexts and languages are predicated on the notion that such efforts take into account distinct groups’ experiences and meanings of health, behaviors, illness, symptoms, disability, and help-seeking behaviors. Assessment instruments developed for use in research applications may not account for cultural, linguistic, or literacy factors, such as limited English proficiency or low literacy, that limit access to such assessments. Consequently, few or no assessments are available that can capture valid and reliable administration and scoring information for these populations.

In addition, the extent and types of medical evidence in an applicant’s file likely will be affected by the availability and cost of tests. Health care data relevant to disability determinations, such as the results of specific, expensive tests (e.g., certain cardiovascular tests and psychological test batteries) that are valid and potentially useful, may not be readily available because an individual may be uninsured or underinsured, or the tests may be denied by an insurance plan because they are not deemed medically necessary. Health disparities can have a significant effect on the availability of health information to inform disability determinations. Disability applicants who are uninsured or underinsured are less likely to have a well-developed body of health data, including the results of expensive, specialized tests, to demonstrate evidence of disability. Disparities in access to care and consequently health outcomes can affect not only the quantity of tests conducted in the context of disability determinations but also the quality of the tests and resulting information. Access to health care professionals, including those with expertise in providing information relevant to disability determination, often is limited by lower socioeconomic status and/or geographic location. Acquisition of an applicant’s clinical records may be difficult for several reasons: providers’ fear of sharing confidential

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×

information, the limited capacity of a provider’s organization to gather and transmit records, and high administrative costs for record transfer.

For these reasons, the committee drew the following conclusion:

  1. A number of factors, including age, gender, lower socioeconomic status, race, ethnicity, cultural group, and geographical location, may limit the quality and quantity of functional information available for a disability applicant.
    • Functional assessment instruments vary in the extent to which they have been tested or adapted across diverse populations, making it important to consider an instrument’s performance across multiple subgroups.
    • Assessment instruments developed for research applications may not account for cultural, linguistic, or literacy factors that influence access to such assessments (i.e., no assessments available for people with limited English proficiency or those with low literacy).
    • Lower socioeconomic status is associated with less access to high-quality care and health care providers with expertise in providing information relevant to disability determination.
    • A number of additional factors limit available information, including cost and administrative challenges (e.g., costs of tests, assembling and sharing medical records).

SUPPORTING EVIDENCE FOR THE COMMITTEE’S OVERALL CONCLUSIONS

Box 9-2 shows the links between the overall conclusions presented above and some of the most relevant chapter-specific findings and conclusions that support them.2

___________________

2 Not all of the committee’s chapter-specific findings and conclusions are included in Box 9-2. Those that are included are numbered according to the chapter in which they appear.

Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
×
Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
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Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
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Suggested Citation:"9 Overall Conclusions." National Academies of Sciences, Engineering, and Medicine. 2019. Functional Assessment for Adults with Disabilities. Washington, DC: The National Academies Press. doi: 10.17226/25376.
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The U.S. Social Security Administration (SSA) provides disability benefits through the Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI) programs. To receive SSDI or SSI disability benefits, an individual must meet the statutory definition of disability, which is “the inability to engage in any substantial gainful activity [SGA] by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months.” SSA uses a five-step sequential process to determine whether an adult applicant meets this definition.

Functional Assessment for Adults with Disabilities examines ways to collect information about an individual’s physical and mental (cognitive and noncognitive) functional abilities relevant to work requirements. This report discusses the types of information that support findings of limitations in functional abilities relevant to work requirements, and provides findings and conclusions regarding the collection of information and assessment of functional abilities relevant to work requirements.

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