Review ArticleThe dilemma of measuring perceived health status in the context of disability
Section snippets
Differentiating Health, Function, and Disability
Understanding the genesis of many current HRQOL measures provides a basis for understanding the current problem of health measurement that is confounded with function. The early roots of perceived health status measurement occurred in a time that preceded contemporary distinctions among health, function, and disability. Historically, disabilities were considered equivalent to chronic health conditions. This perspective is still evident in studies that combine respondents with chronic health
Need for a function-neutral HRQOL measure
Until the early 1970s, health researchers primarily understood the health of populations and research samples in terms of mortality (e.g., how many people died? at what ages did they die?) and morbidity (e.g., how many people are sick? How many people experience symptoms?). This traditional approach to conceptualizing health is still in use [43]. During the last 40 years, health measurement expanded to include measures of perceived health or health status [44], [45]. As a result, a new category
Cognition and Self-Report
There is general agreement that health related quality of life is an internal experience requiring self-report as the form of data collection [10], [11], [40]. A number of models have been proposed that incorporate the process of interpreting questions, memory and recall, and formulating a response [49], [50], [51], [52], [53]. For example, the internal experience of HRQOL is influenced by individuals’ expectations and these expectations can change based on life experiences [54], [55]. Research
Addressing Functional Biases
Items in a measure of perceived health status should demonstrate neutrality relative to functional abilities of respondents. Function neutrality still allows for mean differences between groups, but these differences should represent characteristics of health such as pain, fatigue or depression and not elements of independent function. Development of a function-neutral measure of health would require surmounting three core challenges: (1) operationalizing the concept of function as distinct
Identifying and Neutralizing Functional Bias
In response to the increasing attention given to the constructs of health and function in disability research, members of the ICF Research Branch mapped the items of six popular measures of HRQOL onto the framework of the ICF [64]. Expert judgment determined the allocations. Their analyses clearly demonstrate the great variability across HRQOL measures in emphasis on “body function” versus “activities and participation.” The SF-36 crosses both constructs (14 items in body function, 24
Validation of Function-Free Items
Differential Item Functioning (DIF) analysis is one method for assessing functional bias at the item level while still allowing for mean level differences between groups. Item level DIF scores are computed by calculating the item mean for a disability sample, partialling out the sample's mean score on the domain of interest. This disability sample score is then compared with the corresponding item score for the normative sample which has been similarly adjusted by partialling out the normative
Conclusion
The conceptual distinctions between health and function that have emerged over the past two decades have revealed a measurement dilemma for disability and health researchers. Most current research measures of perceived health status or health related quality of life confound measurement of health with measurement of function. This confounding contributes to a number of problems in calibration, measurement error, respondent burden and erroneous research conclusions. Their use can lead to
Acknowledgments
The RRTC Expert Panel on Health Measurement includes Vincent Campbell, PhD, Centers for Disease Control and Prevention; Brad Cardinal, PhD, Oregon State University; Charles Drum, JD, PhD, Oregon Health & Science University; Glenn Fujiura, PhD, University of Illinois at Chicago; Trevor Hall, PhD, Oregon Health & Science University, Willi Horner-Johnson, PhD, Oregon Health & Science University; Gloria Krahn, PhD, Oregon Health & Science University; Margaret Nosek, PhD, Baylor College of Medicine;
References (65)
- et al.
The role of social support and integration for understanding socioeconomic disparities in self-rated health and hypertension
Soc Sci Med
(2007) - et al.
The disability paradox: high quality of life against all odds
Soc Sci Med
(1999) - et al.
Racially mixed neighborhoods, perceived neighborhood social cohesion, and adolescent health in Canada
Soc Sci Med
(2007) - et al.
Why do Hispanics in the USA report poor health?
Soc Sci Med
(2007) - et al.
Self-rated health and healthy days: examining the “disability paradox”
Disabil Health J
(2008) - et al.
Stress self-management: an intervention for women with physical disabilities
Women's Health Issues
(2006) - et al.
Self-rated health and its relation to all-cause and cardiovascular mortality in Southern Germany. Results from the MONICA Augsburg Cohort Study 1984–1995
Ann Epidemiol
(2002) - et al.
Socioeconomic status and health-related quality of life among elderly people: Results from the Joint Canada/United States Survey of Health
Soc Sci Med
(2008) - et al.
Measuring functional status: cross-sectional and longitudinal associations between performance and self-report (Zutphen Elderly Study 1990-1993)
J Clin Epidemiol
(1996) - et al.
A model of outcomes research: spinal cord injury
Arch Phys Med Rehabil
(2000)
A pilot study to modify the SF-36V physical functioning scale for use with veterans with spinal cord injury
Arch Phys Med Rehabil
Enabling our instruments: accommodation, universal design, and access to participation in research
Arch Phys Med Rehabil
Quality of life issues in individuals with spinal cord injury
Arch Phys Med Rehabil
Self-rated health status as a health measure: the predictive value of self-reported health status on the use of physician services and on mortality in the working-age population
J Clin Epidemiol
Evaluating quality-of-life and health status instruments: development of scientific review criteria
Clin Therap
Smoking status and quality of life: a longitudinal study among adults with disabilities
Am J Prev Med
Health promotion for persons with disabilities: moving beyond rehabilitation
Am J Health Prom
Healthy People 2010
Closing the Gap: A National Blueprint to Improve the Health of Persons With Mental Retardation
The Surgeon General's Call to Action to Improve the Health and Wellness of Persons With Disabilities
Determinants of self rated health for Canadians with chronic disease and disability
J Epidemiol Community Health
International Classification of Functioning, Disability and Health
Quality of life measurement: bibliographic study of patient assessed health outcome measures
BMJ
Health status assessment methods for adults: past accomplishments and future challenges
Annu Rev Public Health
Measuring Healthy Days
Comparing SF-36 scores across three groups of women with different health profiles
Qual Life Res
Tracking healthy days: a window on the health of older adults
Prev Chronic Dis
People with disabilities as a health disparities population: the case of sexual and reproductive health disparities
Calif J Health Prom
Recognizing and responding to the health disparities of people with disabilities
Calif J Health Prom
Survival, functional limitations, and self-rated health in the NHANES I epidemiologic follow-up study, 1992
Am J Epidemiol
Healthy lifestyles for people with disabilities
Calif J Health Prom
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Putting “ME” into measurement: Adapting self-report health measures for use with individuals with intellectual disability
2022, Research in Developmental DisabilitiesMeasurement characteristics for two health-related quality of life measures in older adults: The SF-36 and the CDC Healthy Days items
2016, Disability and Health JournalCitation Excerpt :The key concern is that items assessing functioning used to assess HRQOL may result in artificially low scores for people with disabilities. Importantly, the extent of this reduction is not always clear and likely differs by disability type.8,20 A similar DIF analysis of the CDC Healthy Days items showed very little evidence of negative DIF for people with disabilities.21
Pregnancy among US women: Differences by presence, type, and complexity of disability
2016, American Journal of Obstetrics and GynecologyCitation Excerpt :They also tended to be older, poorer, less educated, less employed, and less healthy than women without disabilities. However, the majority of women with disabilities reported positive perceived health, consistent with prior survey research22,23 and with conceptual models distinguishing disability from poor health.24 Within our sample, 12.1% of women had reported pregnancies during 1 year of their panel participation.
Social participation and health-related quality of life in people with multiple sclerosis
2015, Disability and Health JournalCitation Excerpt :On the other hand, it measures social participation with far fewer items, does not involve the concept of peer comparison and is only a small part of the MCS dimension, with no links to PCS, which is the reason why we decided to use this measurement. Finally, HRQoL measured by the SF-36 can be considered as not entirely accurate, as this measurement is closely linked with functional status rather than with health, and functional limitation may be the reason for the negative bias.28 This study is beneficial in that it shows that social participation is very important for PCS in people with MS. According to our results, isolation and avoiding social activities are associated with lower HRQoL in people with MS. Hiding from social activities may seem comfortable and easy, as it eliminates the stress from obstacles to social participation caused by health problems, but this study indicates that there is an association between social participation and PCS.
Integration of chronic disease and disability and health state programs in Montana
2014, Disability and Health JournalEvidence of item bias in a national flourishing measure for autistic youth
2023, Autism Research
The authors have no financial disclosures or conflicts of interest to declare.