The International Classification of Functioning, Disability and Health: the first 20 years

Abstract

On 22nd May 2001, the World Health Organization’s (WHO) International Classification of Functioning, Disability and Health (ICF) was formally endorsed by 191 countries at the 54th World Health Assembly in Geneva, Switzerland. Although broadly anticipating the wide range of applications of the ICF in clinical care, public health, and health sciences research, WHO’s own specific aim was to realize its constitutional mandate to collect and disseminate internationally comparable health information. To do so it needed to create a standard international language to describe and measure health and functioning. The intention was to augment WHO’s International Classification of Diseases and Related Health Problems (ICD) with a classification of the experience of living with a health condition, and the determinants of that experience, both intrinsic to the person and external or environmental. This was achieved by means of the ICF’s underlying conceptual model that embodied a fundamental shift in the understanding of disability in terms of the ICF central concept of functioning. Twenty years on, the volume of literature applying the ICF has exploded. The ICF embodied a paradigm shift. Although the state of a person’s health was intrinsic to the individual, the experience of health and disability depended on the physical, human-built, attitudinal, and socio-political environment in which the individual lived. This was a revolutionary shift in approach. Both clinical practice and research now needed to include – but also go beyond – biomedical and psychosocial dimensions to incorporate the full scope of the overall environment. Not long after the ICF was endorsed, researchers saw the value of the ICF as a new research and clinical tool, especially for pediatric neurorehabilitation of children with complex disabilities. Within a few years, researchers began to use the ICF to report findings of systematic, scoping, and other literature reviews; to compare the content of popular generic instruments; and to generally adopt the conceptual terminology and coding language of the ICF. Some researchers emphasized the value of the ICF as a framework for describing intervention outcomes and developing needs assessment tools. Recognizing the importance of facilitating the application of the ICF in day-to-day clinical practice and providing a practical information platform for routinely collected data, work began on creating ICF Core Sets for three major childhood-onset health conditions: cerebral palsy, autism spectrum disorder, and attention-deficit/hyperactivity disorder. ICF Core Sets development required a time-consuming, highly rigorous, and multi-study methodology, but the end result constituted a substantial contribution to clinical practice. Equally valuable was the development of Common Data Elements for children and young people with cerebral palsy, based on the ICF framework, that could guide the standardization of data collection and outcome evaluation in the field. Recently, the ICF language and framework have been proposed as the basis for family-centered goal setting for children in inpatient rehabilitation. Time and again, the ICF has proven its worth across a wide range of applications in clinical practice, public health, health information, and health sciences. There is little doubt that the next 20 years will continue this trend and the ICF will be here to provide both the conceptual framework and international common language of health, functioning, and disability.