It endorses the adoption of the conceptual framework published by the World Health Organization (WHO) in 2001 as a means of promoting clear communication and building a coherent base of national and international research findings to inform public and private decision making. At the same time, it identifies several directions for refining and improving that framework to better serve monitoring (surveillance), research, and public policy purposes. The chapter also reviews current disability monitoring activities, evaluates progress since publication of the 1991 and 1997 Institute of Medicine (IOM) reports on disability, and sets forth recommendations for further improvements in monitoring programs.


A significant feature of the 1991 IOM report Disability in America was the conceptual framework that it set forth for understanding disability not only as a series of consequences of disease or injury but as a consequence of people’s relationship with their environments—environments that might be supportive of participation in society or that might present obstacles to such participation. Building in particular on the work of Saad Nagi (1965, 1991), it attempted to define a common language for describing and understanding disability and related concepts. The report used the following definitions of stages in the process by which people acquire disabilities or improve their functioning in the context of a particular social and physical environment:

  • Pathology: “interruption or interference of normal bodily processes or structures caused by disease, trauma, or other conditions”

  • Impairment: “loss and/or abnormality of mental, emotional, physiological, or anatomical structure or function; includes all losses or abnormalities, not just those attributable to active pathology; also includes pain”

  • Functional limitation: “restriction or lack of ability to perform an action or activity in the manner or within the range considered normal that results from impairment”

  • Disability: “inability or limitation in performing socially defined activity and roles expected of individuals within a social and physical environment;” also, a “gap between a person’s capacities and the demands of relevant, socially defined roles and tasks in a particular physical and social environment” (IOM, 1991, pp. 79–81)

The 1997 IOM report Enabling America relied on the 1991 IOM conceptual framework but made some refinements related, in particular, to clarifying the interaction between the person and the environment and

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