International Classification of Functioning, Disability and Health (ICF)
A related major conceptual model developed to guide research and to assess functional status need is the International Classification of Functioning, Disability and Health. Originally created through the support of the World Health Organization (WHO) as the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) (WHO, 1980), the ICF is an assessment tool that captures a broad array of information relating to health and functioning (WHO, 2001).
The ICF describes health and health-related conditions in terms of an interaction between functioning, disability, and contextual factors. Functioning and disability are structured around two broad components:
The first set of components focuses on assessing body functions and body structure. The second set focuses on assessing capacity and performance. Since individual functioning and activity participation occur within a context, the ICF includes the contextual factors of environmental facilitators and barriers as well as personal factors (i.e., severity) (WHO, 2001). The result is an assessment that views functioning and disability as the complex interaction between individual health and contextual and personal factors. The recognition of the role of the environment on health and well-being for people living with a disability is a critical element for public health interventions. Ideally, use of the ICF will allow public health and health practitioners to identify which components of an individual’s functioning are being addressed by a particular intervention.
Disability Surveys & Prevalence Estimates
A number of national surveys have been or are conducted by US federal agencies, including the US Bureau of the Census and the Centers for Disease Control and Prevention. Although population estimates are available through these efforts, their primary purposes are tied to program mandates and not necessarily to generating surveillance data. Moreover, different definitions of disability are often used in these efforts. For example, the US Bureau of the Census uses a combined medical and functional approach to disability in the decennial Census and in the American Community Survey.
The Behavioral Risk Factor Surveillance System (BRFSS) is the nation’s largest public health telephone survey. It is an annual survey conducted in every state and territory with the non-institutionalized population. Previously, a disability module or identifiers were implemented in a number of states on an intermittent basis. In 2001, two disability identifiers were added to the core modules of the BRFSS and, since 2003, basic data for this group are now available annually from every U.S. state and territory. In the BRFSS, disability is defined as being limited in any way in any activities because of physical, emotional, or mental problems, or as having any health problems that require the use of special equipment (Centers for Disease Control and Prevention [CDC], 2004).