Functioning (r)evolution: from vision to practice

The World Health Assembly’s (WHA) adoption of the International Classification of Functioning, Disability, and Health (ICF) almost 22 years ago was a revolutionary step toward global recognition of the critical role functioning plays in our conception of health. Although the key points made by Bickenbach et al. in their Frontiers in Science article (1) are logical and often inarguable, the wide-ranging and methodical inclusion of functioning into public policies and practice—from healthcare to social protection systems—has admittedly been slow. Valiant but somewhat isolated efforts have been made by the World Health Organization (WHO), the physical medicine and rehabilitation communities, researchers, and WHO ICF Collaborating Centres, but universal adoption of functioning as a health criterion has yet to be achieved. Disability-assessment systems, in which the need to assess functioning should be obvious, are the most glaring example of this slow progress. Even in countries that have incorporated elements of functioning into their disability-assessment procedures, medical doctors are still the dominant cadre of assessors, and assessment criteria mainly infer disability from medical conditions (2, 3, 4). 

Contributing factors at various levels 

Several factors are likely to contribute to the slow adoption of functioning into health assessment. At the global level, even though the ICF is the WHO’s framework for assessing health and disability, the Organization’s resources and capacity for worldwide promotion of this concept are constrained. Ongoing efforts appear spread across several units with different interpretations of functioning. Apart from the International Society of Physical and Rehabilitation Medicine, no other big players have been making a case for the international development of functioning as a health criterion. 

At the country level, familiarity with the concept of functioning appears limited, even within health-focused government agencies. In countries where consideration is given to functioning, it is often solely in the context of disability assessment—not as a universal issue permeating a host of public-policy areas and pertinent to all humans across the lifecycle.  

High-level champions of functioning are rare, even in the context of disability assessment. Much persuasion will be required to unite stakeholders behind broad incorporation of functioning into assessment practices. Medical doctors involved in disability assessment may be particularly difficult to convince as they are often skeptical about functioning, describing it as “subjective” and “vulnerable to fraud” in contrast to “objective” medical assessments.1 Even those fully supportive of functioning’s inclusion in disability assessment occasionally slip into these arguments, illustrating that deeply ingrained beliefs and long-held practices are not easily overcome—no matter how logical, beneficial, and commonsensical new approaches may be. 

Additionally, some disability organizations and disability-rights advocates voice concerns that certain people with disabilities may lose benefits if disability assessment considers functioning. On the other hand, government representatives express fear that the number of people qualifying for disability benefits will increase with the inclusion of functioning into assessment. Empirical research based on WHO Disability Assessment Schedule (WHODAS) pilot data does not corroborate either concern (6, 7, 8).  

WHODAS as a measurement option 

At the technical level, measurement of functioning (and thus disability) remains a major roadblock for the inclusion of functioning in public policies. To be used along with mortality and morbidity as an indicator of health, as proposed in Bickenbach et al. (1), international agreement must be reached on a suitable, accurate indicator of functioning (9), including its method of calculation and common instruments for data collection. Thus far, two instruments based entirely on the ICF conception of functioning have proven psychometrically and statistically sound: the WHO/World Bank Model Disability Survey and WHODAS. I will focus on the latter. 

WHODAS was developed by WHO as a practical 12- and 36-question tool to assess an individual’s functioning in the six ICF core functioning domains: understanding and communicating, getting around, self-care, interpersonal relationships, life activities, and participation in society (10). The overall score represents a summary of the whole-person level of functioning. Results are clear and easy to interpret. WHODAS can be used irrespective of underlying health conditions and can be administered in various settings to enhance clinical practice, research, education, and policy development. Data gathered by WHODAS can be disaggregated by International Classification of Diseases codes, domains of functioning, demographic and social characteristics, and other parameters. As of the last systematic review in 2017, WHODAS had been used in at least 810 relevant studies from 94 countries, to assess functioning and disability related to various health conditions in multiple settings (11).   

Between 2018–2022, the World Bank and the European Commission supported Greece, Latvia, Lithuania, and Bulgaria in piloting WHODAS as part of each country’s efforts to include an ICF-based conception of functioning into their respective disability-assessment and determination systems. Comprehensive statistical analyses of these large-sample pilot studies confirmed that WHODAS successfully collects functioning information, and that data are psychometrically robust, with strong validity and reliability. In these pilot countries, WHODAS was demonstrated to measure whole-person disability, create summary scores, and provide objective, accurate assessments of functioning based on ICF core functioning domains. Consequently, country-specific options for including functioning into disability-assessment procedures were proposed in all four of these countries (6, 7, 8).  

Mainstreaming functioning 

To make the vision of a functional component of health into a reality, a much more concerted effort is needed. WHO could spearhead this effort by increasing available resources and by consolidating its efforts in this regard, including stepping up support to member states to assist incorporation of WHODAS into disability-assessment systems. As tens of millions of people across the world undergo disability assessments each year, WHODAS would enable the annual collection of statistically robust, internationally comparable functioning data. WHO could also adopt a WHA resolution aimed at mainstreaming functioning and measurement of functioning in health assessment and could encourage the commitment of member states to act on the resolution. Further, to bolster basic knowledge of functioning as a critical component of health, the concept of functioning should be widely incorporated into both medical education curricula and training programs for government officials.  

References 

1. Bickenbach J, Rubinelli S, Baffone C, Stucki G. The functioning revolution: implications for health systems and sciences. Front Sci (2023) 1:1118512. doi: 10.3389/fsci.2023.1118512 

2. Posarac A, Celmina E, Bickenbach J. Latvia—disability policy and disability assessment system. European Commission and World Bank Group (2020). Available at: https://documents.worldbank.org/en/publication/documents-reports/documentdetail/099310306132234252/p1716470e9f0a20be0996100b15852cadd3/  

3. Posarac A, Bickenbach J. Lituhuania—disability policy and disability assessment system. European Commission and World Bank Group (2020). Available at: https://documents.worldbank.org/en/publication/documents-reports/documentdetail/099310106132231429/p171647016fc0e0b70b0b90bf17dc1b97bd/  

4. Waddington L, Priestley M, Sainsbury R. Disability Assessment in European States ANED Synthesis Report. Soc Sci Res Network (2019). Available at: https://ssrn.com/abstract=3320419   

5. Working Group on the Assessment of Person-Related Criteria for Allowance and Personal Assistance for People with Disabilities. Assessing disability in Europe, similarities and differences. Integration of people with disabilities. Council of Europe (2002). Available at: https://rm.coe.int/16805a2a27/  

6. Felinghauer C, Posarac A, Bickenbach J, Jasarevic M. Options for including functioning into disability and work capacity assessment in Latvia. World Bank Group (2022). Available at: https://documents.worldbank.org/en/publication/documents-reports/documentdetail/099310406132218525/p17164708e0cab0f00a8f7063026f9cdab4 

7. Posarac A, Felinghauer C, Bickenbach J. Options for including functioning into disability and work capacity assessment in Lithuania. World Bank Group (2022). Available at: https://documents.worldbank.org/en/publication/documents-reports/documentdetail/099310106132229174/p17164709d22130600b2a20bbd8bd364ece/  

8. Fellinghauer C, Posarac A, Bickenbach J, Jasarevic M. Bulgaria: Options for Including Functioning into Disability Status Assessment. World Bank Group (2022). Available at: https://policycommons.net/artifacts/3330619/bulgaria/4129448/fragments/ 

9. Brown D. Good practice guidelines for indicator development and reporting. Third World Forum on ‘Statistics, Knowledge and Policy’ Charting Progress, Building Visions, Improving Life (2009). Available at: https://www.oecd.org/site/progresskorea/43586563.pdf  

10. World Health Organization. Measuring health and disability: manual for WHO disability assessment schedule (WHODAS 2.0). Üstün T, Kostanjsek N, Chatterji S and Rehm J, eds. (2010). Available at: https://www.who.int/publications/i/item/measuring-health-and-disability-manual-for-who-disability-assessment-schedule-(-whodas-2.0) 

11. Federici S, Bracalenti M, Meloni F, Luciano JV. World Health Organization disability assessment schedule 2.0: an international systematic review. Disabil Rehabil (2017) 39:23. https://doi.org/10.1080/09638288.2016.1223177