APPENDIXES



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Disability in America: Toward a National Agenda for Prevention APPENDIXES

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Disability in America: Toward a National Agenda for Prevention This page in the original is blank.

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Disability in America: Toward a National Agenda for Prevention A Disability Concepts Revisited: Implications for Prevention Saad Z. Nagi* The significance of disability as an individual and a societal concern cannot be overstated. Whether measured in prevalence or in social and economic consequences, the impacts are daunting. Although the questions they ask may be phrased somewhat differently, comprehensive disability surveys are fairly consistent in estimating that about 6.5 percent of noninstitutionalized Americans ages 18 through 64 are so severely disabled that they are not able to work (see, for example, Nagi, 1976; Social Security Administration, 1981, 1982). Estimates of the number of people who are limited in the amount or kind of work they can do, but who are not totally prevented from working, very widely; on average, however, they constitute an additional 6.5 percent of the same sector of the population (Haber, 1990). These figures mean that about one in every eight adults in the United States in these age categories is disabled or limited in vocational pursuits. Furthermore, 1.8 percent of the noninstitutionalized civilian U.S. population 18 years of age and older need assistance in personal care; 3.5 percent need assistance in shopping, housework, and outdoor mobility; and 6.3 percent are limited in performing these activities of daily living but do manage to carry them out independently (Nagi, 1976). Most societies, especially those of the industrialized world, have developed various types of programs of benefits and services. These programs provide another way of estimating the magnitude of the problem in terms of numbers of beneficiaries (Sunshine, 1980). During the early 1980s there were about 915 million beneficiaries of long-term disability programs in this country. (Some people may have been counted more than once, however, if they derived benefits from more than one program.) Social Security *   Ohio State University

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Disability in America: Toward a National Agenda for Prevention Disability Insurance, Supplemental Security Income, and Veterans Compensation programs are the largest contributors to this total. These three programs alone account for nearly three-quarters of all beneficiaries of long-term disability benefits. The picture of temporary disability and workers' compensation is not as clear because of the continuous movement of beneficiaries into and out of these programs. These programs handle an estimated 2 million persons at any given point in time. The economic dimension of disability is equally massive. Total expenditures for disability-related transfer payments and health care for the disabled reached $114.2 billion in 1975 (Berkowitz and Rubin, 1978), a hefty 7.5 percent of the gross national product (GNP). These expenditures have been rising at faster rates than the GNP. They were $69 billion in 1970 and only $39 billion in 1967, representing 6 percent and 4.9 percent of the GNP, respectively, in those two years. Regarding the sources of the $114.2 billion spent in 1975, $56.7 billion came from the federal government (including matching funds), $13.7 billion from state and local governments, and $43.7 billion from the private sector. Two factors influence these figures: numbers of beneficiaries and levels of benefits. As a percentage of governmental expenditures in the United States, income support for the disabled grew from 5.8 percent to 8 percent during 1968-1978 (Haveman et al., 1984). The annual rate of growth during that period was 6.3 percent in real terms. To place these estimates in a comparative perspective, the rates of growth in the percentage of governmental expenditures for income support for the disabled amounted to 0.5 percent in the United Kingdom, 5.3 percent in Germany, 12.1 percent in Sweden, and 18.6 percent in the Netherlands. Society has evolved certain policies, programs, and professions that address the prevention of disability and the alleviation of its consequences. In the United States, which is a democratic, pluralistic society, these developments have been incremental and uneven, producing an unintegrated set of programs that are not unlike immiscible liquids that defy integration. Adapted from varying traditions (but mostly European in origin), the programs as a body are characterized by serious gaps and unnecessary overlaps. In spite of the substantial prevalence and consequential effects of disability on individuals, families, and society, related conceptual and theoretical developments are of recent origin. The field is much in need of a theory to guide and advance research, to enhance understanding on the part of the professions and the public at large, and to better focus related policies and programs and improve their effectiveness. By theory I do not mean speculation but rather a set of interrelated concepts and empirically testable propositions that describe the phenomenon of disability and explain variance in its occurrence. Fundamental to the development of such a theory is a conceptual analysis to clarify the nature of disability and its dimensions. This paper addresses that objective.

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Disability in America: Toward a National Agenda for Prevention CONCEPTUAL HISTORY Early attempts at conceptualizing disability and its dimensions were prompted by influences from several sources. Three are particularly important: rehabilitation, chronic diseases, and compensation and insurance benefits. There have been important shifts in the concept and programs of rehabilitation from those espoused in the Vocational Rehabilitation Act of 1920. This act rejected calls for a comprehensive program that would include medical and surgical services and limited the concept of rehabilitation in the main to vocational training. The act was administered by state departments of education along with vocational education. There followed a move to the concept of comprehensive services, which allowed for ''corrective" surgery, therapeutic treatments to reduce or eliminate disability, hospitalization, education, equipment, licenses, and tools (Switzer, 1965). State commissions for rehabilitation were established as separate agencies or placed under departments of public welfare. In 1953 the U.S. Department of Health, Education, and Welfare assumed responsibility for the reorganized Federal Security Agency, including the administration of vocational rehabilitation. Another milestone was the Vocational Rehabilitation Act of 1954, which adopted a formula for federal-state financing. The act permitted "the establishment of comprehensive rehabilitation facilities; the creation of specialized clinics of speech, hearing, cardiac, and other disorders; and the development of a variety of services that at one time would have seemed unattainable" (Switzer, 1965). The 1943 and 1954 rehabilitation acts led to the infusion of funds into the field of rehabilitation, the spread of comprehensive centers, and the involvement of many disciplines—including medicine, education, social work, psychology, vocational counseling, occupational therapy, and nursing, among others. Inevitably, this broad professional grouping led to competition over resources and concerns over the protection of professional domains (e.g., Hamilton, 1950; Wright, 1959). (Indeed, the issue of domains continues to linger and is expressed in a variety of forms [Nagi, 1975].) These developments set the stage for attempts at conceptual distinctions to delineate the roles of the different professions and to explain their interrelationships. For example, Hamilton (1950) distinguishes between disability and handicap: disability is "a condition of impairment, physical or mental, having an objective aspect that can usually be described by a physician. It is essentially a medical thing"; a handicap is "the cumulative result of the obstacles which disability interposes between the individual and his maximum functional level." Hamilton goes on to say that "it is the handicap, not the disability, that gives impairment its welfare significance." Several notable efforts during the 1950s contributed to advances in conceptualization and measurement of disability. During the first half of the decade, the Commission on Chronic Illness (1957) conducted two comprehensive

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Disability in America: Toward a National Agenda for Prevention surveys in Baltimore, Maryland, and Hunterdon County, New Jersey. One of the objectives was to obtain estimates for the "prevalence of illness and disability resulting from chronic disease by diagnosis, degree and duration of disability." Three kinds of measures of the disabling effects of chronic conditions were used in the evaluation: (1) limitations on the ability to perform 11 selected activities of daily living; (2) limitations on overall functional capacity; and (3) limitations on the ability to work, keep house, or attend school (i.e., the person's usual major activity). The second measure remains one of the best scales for independent living. The third measure of limitations in roles, referred to here as activities, is an approach that has been used for decades in the National Health Interview Survey (National Center for Health Statistics, 1987a). Interest in functional assessments during the 1940s and 1950s spurred the development of measures of functional deficits—what Deaver and Brown (1945) called "activities of daily living" (ADL). A variety of instruments were constructed including differing combinations of items (for an informative review, see Gresham and Labi, 1984). A review of ADL scales led Hoberman and Associates to conclude in 1952 that "daily activity measurement will have passed adolescence only when functional tests are properly graded, scored, validated, and normed, and their all-round practicability and utility demonstrated." More than 30 years later, Frey (1984) declared, "it is safe to say that, with the exception of only a very few ADL scales, development in this area remains preadolescent." In addition to the work of the Commission on Chronic Illness noted above, other notable efforts in the area include those of Lawton (1972), Lambert and colleagues (1975), and Katz and co-workers (1963, 1983). The decade of the 1950s was marked by mounting concerns over criteria and decisions regarding compensation and other disability benefits, which led to other conceptual attempts—for example, by the American Medical Association (AMA) Committee on Medical Rating of Mental and Physical Impairment (1958). The committee's work was in response to the needs of workers' compensation programs—which had been plagued by litigations— to develop standardized ratings legitimized by the professional and scientific standing of the AMA. The committee distinguished between impairment and disability by pointing out that "permanent impairment is a contributing factor to, but not necessarily an indication of, the extent of a patient's permanent disability." To the committee, "[c]ompetent evaluation of permanent impairment requires adequate and complete medical examination, accurate objective measurement of function and avoidance of subjective impressions and non-medical factors such as the patient's age, sex, or employability." Because the committee's domain was defined as that of impairment, disability was left without further clarification. What is important, however, is the reference to the functional dimension. Such a reference was also included in a report by the Criteria Committee of the New York Heart Association

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Disability in America: Toward a National Agenda for Prevention (1953), which described a complete diagnosis as accounting for etiological, anatomical, physiological, functional, and therapeutic aspects. Individual clinicians also developed approaches to measuring functional losses (e.g., McBride, 1963; Kessler, 1970). A CONCEPTUAL FRAMEWORK As the 1950s drew to a close, the situation was one of differing conceptions of disability and related phenomena and no shared concepts; a number of terms were applied unsystematically and often interchangeably. The lack of clarity in conceptual constructs was reflected in problems with criteria for the evaluation of disability for compensation and other benefits. The various programs relied heavily on impairment schedules and lists for their decisions concerning disability in vocational roles and earning potentials. In a sense, this corresponds to the analogy of looking for a key in a place where there happens to be some light rather than where the key was dropped. In regard to workers' compensation programs, the AMA Committee on Medical Rating of Mental and Physical Impairment (1958) concluded that "impairment is, in fact, the sole or real criterion of permanent disability far more often than is readily acknowledged." In a similar vein, the Subcommittee on Social Security of the House Ways and Means Committee (1959) gave the following instructions: The Subcommittee recognizes the difficulties of developing and enunciating criteria for the weight to be given non-medical factors in the evaluation of disability and the extreme sensitivity of this area. But the Subcommittee believes that the time has come, if it is not well overdue, to make a determined effort to develop and refine these criteria and make them available to the evaluators and to the public in the form of published regulations. The decade also witnessed provisions for research development in the 1954 Rehabilitation Act and in other programs, which introduced the research community more extensively to disability and rehabilitation issues. In the early 1960s, as part of plans for a large-scale study of decision making in the Social Security Disability Insurance (SSDI) program and in rehabilitation services for SSDI applicants and beneficiaries, Nagi (1964, 1965, 1969) built on existing knowledge to construct a framework of four distinct but interrelated concepts: active pathology, impairment, functional limitation, and disability. The state of active pathology may result from infection, trauma, metabolic imbalance, degenerative disease processes, or other etiology. Such a condition involves (a) interruption of or interference with normal processes, and (b) the simultaneous efforts of the organism to regain a normal

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Disability in America: Toward a National Agenda for Prevention state. Pathology then is not merely the surrender to an abnormal state of affairs but also the fight for health (Selye, 1956). Obviously, deficiencies in immune systems and other coping mechanisms can render the fight for health ineffective. In modern health practices, the organism is aided by surgical intervention, medication, and other forms of therapy to help regain equilibrium. Some means may become necessary over extended periods of time or indefinitely, as in the case of certain types of chronic diseases. The concept of impairment indicates a loss or abnormality of an anatomical, physiological, mental, or emotional nature. The concept comprises three distinct categories: (1) all conditions of pathology, which are by definition impairments because such conditions involve anatomical, physiological, mental, or emotional deviation; (2) residual losses or abnormalities that remain after the active state of pathology has been controlled or eliminated (e.g., healed amputations, residual paralysis); and (3) abnormalities not associated with pathology (e.g., congenital formations). Thus, although every pathology involves an impairment, not every impairment involves a pathology. Impairments vary along a number of dimensions that affect their influence on the nature and degree of disability. Important among these are the degree of visibility and disfigurement, stigma, the predictability of the course of the underlying pathology, the prognosis and prospects for recovery or stabilization, threat to life, the types and severity of limitations in function they impose, and the point of onset in the life cycle—congenital, early childhood, during the productive years, or later in life. Functional limitations and impairments both involve function. The difference, however, is in the level at which the limitations are manifested. Functional limitation refers to manifestations at the level of the organism as a whole. Many tissues, for example, may have an altered structure or function without limiting the ability of the organism as a whole. A significant number of muscle fibers must become denervated before discernible weaknesses occur; the walls of blood vessels must undergo a great deal of alteration before appreciable changes in the flow within these vessels ensure. Virtually an infinite number of similar examples can be noted. One could speak of limitations in function at the levels of molecules, cells, tissues, organs, regions, systems, or the organism as a whole. Although limitations at a lower level of organization may not be reflected at higher levels, the reverse is not true. An individual who is unable to reach overhead because of tightness in the shoulder can be expected also to have abnormalities at the levels of tissues and cells that make up the shoulder. It is important to note that limitations in function at higher levels of organization may result from differing impairments and limitations in function at the lower levels. For example, inability to lift a heavy weight may be related to mechanical problems in the lumbosacral region, or it may be the result of diminished cardiac output or pulmonary ventilation (Melvin and Nagi, 1970). Functional

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Disability in America: Toward a National Agenda for Prevention limitations are the most direct way through which impairments contribute to disability. However, as mentioned earlier, certain disfiguring or stigmatizing impairments can lead directly to disability without the involvement of a functional deficit at the level of the organism as a whole. Disability refers to social rather than to organismic functioning. It is an inability or limitation in performing socially defined roles and tasks expected of an individual within a sociocultural and physical environment. These roles and tasks are organized in spheres of life activities such as those of the family or other interpersonal relations; work, employment, and other economic pursuits; and education, recreation, and self-care. Not all impairments or functional limitations precipitate disability, and similar patterns of disability may result from different types of impairments and limitations in function. Furthermore, identical types of impairments and similar functional limitations may result in different patterns of disability. Several other factors contribute to shaping the dimensions and severity of disability. These include (a) the individual's definition of the situation and reactions, which at times compound the limitations; (b) the definition of the situation by others, and their reactions and expectations—especially those who are significant in the lives of the person with the disabling condition (e.g., family members, friends and associates, employers and co-workers, and organizations and professions that provide services and benefits); and (c) characteristics of the environment and the degree to which it is free from, or encumbered with, physical and sociocultural barriers. Further clarifications of some issues concerning this framework were made earlier (Nagi, 1975); others are added here in response to questions and misinterpretations arising in professional meetings or in print. First is the issue of its applicability to mental and emotional conditions. The question reflects the position that mental and emotional conditions are more socially grounded than those of an anatomical and physiological nature (e.g., Lemert, 1951; Sullivan, 1953; Scheff, 1967; Szaz, 1974) and therefore do not conform to the same characteristic patterns. Equally important is that, except for organically beset conditions, indicators of pathology, impairment, and functional limitations are, so far, not separable in regard to mental and emotional conditions. In these cases, pathology and impairment are inferred from manifestations at the level of functional limitations. In psychiatric terminology there is reference to "functional" versus "organic" disorders. It is important to note, however, that distinctions between indicators of functional limitations and those of disability can be established with sufficient clarity. Intelligence tests, scales of psychophysiological reactions, other psychometric tests, and clinical assessments have been used to identify functional limitations independent of whether, and to what extent, a person is limited in performing expected roles and tasks.

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Disability in America: Toward a National Agenda for Prevention The second issue concerns distinctions between disability and other forms of inability. Consider, for example, work and employment, which are affected by a variety of factors other than those identified in this framework. Ability or inability to perform social roles, vocational in this example, depends on an interaction between a set of individual characteristics and factors of a situational or environmental nature. A change in the economic or technological environments may lead to unemployment totally unrelated to health conditions. By the same token, family roles may be disrupted or altered by divorce, separation, or other expressions of incompatibility rather than impairment and functional limitation. It is important to reiterate that this framework is rooted within the context of health. Third is the observation that the term disability implies a change from prior higher levels of functioning and is not applicable to congenital and early childhood conditions. In this respect, distinctions have been made between congenital and "adventitious" inabilities (Carroll, 1961), the latter being disability in the strict sense of the word. In this framework, however, the concept of disability is used in a generic sense to include those arising from congenital and early childhood conditions as well as those occurring later in life. The comparative reference for the former is the level of functioning of cohorts rather than of prior levels once maintained. A fourth issue concerns the lines of differentiation between functional limitations and disability and where such activities as those of daily living and use of transportation fit within the concepts of social roles and tasks. To Parsons (1958), "a role is the organized system of participation of an individual in a social system." Roles, looked at that way, constitute the primary focus of the articulation and hence interpenetration between personalities and social systems. Tasks on the other hand, are both more differentiated and more highly specified than roles, one role is capable of being analyzed into a plurality of different tasks… [it] is legitimate to consider the task to define the level at which the action of the individual articulates with the physical world. … A task, then, may be regarded as that subsystem of role which is defined by a definite set of physical operations which perform some function or functions in relation to a role. Sarbin and Allen (1968) differentiate between role expectations and role enactment. "Role expectations are comprised of the rights and privileges, the duties and obligations of any occupant of a social position in relation to persons occupying other positions in the social structure…. Overt conduct, that is, what the person does and says in a particular setting is the first specification of the role enactment." Typically each person performs multiple roles not only because of occupying multiple social positions but also because each position involves a role-set (Merton, 1957). Thus the position of a medical student "entails not only the role of a student in relation to his

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Disability in America: Toward a National Agenda for Prevention teachers, but also to other students, nurses, physicians, social workers, medical technicians, etc." The point to be made is that components of roles—expectations, acts, actions, and tasks—are learned, organized, and purposeful patterns of behavior and not isolated muscle responses (Sarbin and Allen, 1968). Some acts, actions, and tasks are role specific, whereas others are common to the enactment of more than one role. Activities of daily living are learned, organized, and purposeful patterns of behavior. They are part of the set of expectations inherent in family, vocational, and a variety of other roles. Severe limitations in performing these tasks often result in reciprocal role relationships of dependency/assistance, which at times become contractual. The same reasoning applies to driving, the use of public transportation, the use of means of communication, and similar tasks, each of which separately does not constitute a social role but is part of many roles. Limitations in performing these tasks are components of the concept of disability. The fifth issue concerning the disability framework relates to another criterion for differentiating the concept of disability from those of functional limitations, impairment, and pathology. For this, it will be useful to consider differences between concepts of attributes and properties on the one hand and relational concepts on the other (Cohen, 1957). Concepts of attributes and properties refer to the individual characteristics of an object or a person, such as height, weight, or intelligence. Indicators of these concepts can all be found within the characteristics of the individual. Pathology, impairment, and functional limitations are concepts of attributes and properties. One need not go beyond examining a person to identify the presence and extent of physiological and anatomical losses or disorders, or to assess limitations in the functioning of the organism. In contrast, indicators of a relational concept cannot all be accounted for among the attributes of an individual. They include characteristics of other segments of the situation. Disability is a relational concept; its indicators include individuals' capacities and limitations, in relation to role and task expectations, and the environmental conditions within which they are to be performed. The sixth and final issue is the question of whether disability, as conceptualized here, is limited to work. By now, it should be clear that the answer is no. Because of emphasis in public policy on concerns with dependence in economic and personal terms, and greater availability of support for studies of these dimensions, research developments were pushed largely in the direction of work disability and problems in independent living. However, the concept is inclusive of all socially defined roles and tasks. For heuristic purposes, Nagi (1969) applied a stress curve (Koos, 1954; Hill, 1958) to illustrate the processes of disability. As depicted in Figure A-1, the line between (a) and (b) represents the usual level of performance of an individual. The minor fluctuations are within the individual's margin of

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Disability in America: Toward a National Agenda for Prevention FIGURE A-1 Applying a stress curve to illustrate the processes of disability. Adapted from Nagi, 1969; used with permission of Ohio State University Press. tolerance. The major emphasis during such periods is on primary prevention to maintain performance at that level. At point (b) a health condition occurs (disease or injury) that results in a deviation from normality that is beyond the individual's tolerance and coping abilities. The condition is in an acute stage, and the major emphasis is on treatment until the pathology is eliminated or controlled as represented by point (c). (Failure to control the pathology would, of course, result in death.) An important feature of the stress curve is the angle of recovery, that is, the angle formed by the two lines (b)-(c) and (c)-(d). In many cases the recovery is complete; in others a residual impairment may be precipitated. The angle of recovery implies a relationship between time and level of recovery. A smaller angle indicates shorter time and higher level of recovery, and vice versa. Once the condition has been stabilized after (c), the major emphasis shifts from treatment to restoration and rehabilitation. This model is most appropriate for injuries and diseases that have identifiable onsets and for those that have stable residuals. Other models are better suited for describing the increasingly prevalent, gradually progressive chronic conditions that are forcing reassessments of approaches in all phases of health care. In the natural history of these pathologies and the limitations they precipitate, points (b) and (c) in Figure A-1 become less, if at all, identifiable. The residuals are hardly stabilized, and the prognosis is less certain. The dotted line (a)-(e) shows this pattern. The course of these conditions often involves acute episodes. The same curve can be used to illustrate the different forms of functional limitations: physical, sensory, emotional, intellectual, and so on, as well as disabilities in the various roles and tasks (e.g., vocational, family, interpersonal and community relations, independent living). Such mapping requires

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Disability in America: Toward a National Agenda for Prevention meaningful concepts, valid and sensitive measures, and longitudinal data. It should yield information useful for studying the natural history of disability, accounting for factors that influence its course, identifying the types of services and benefits needed, and timing these services and benefits for optimal effectiveness. A FRAMEWORK FROM THE WORLD HEALTH ORGANIZATION In 1980 the World Health Organization (WHO) published a "manual of classification relating to the consequences of disease." In an introduction to this manual, Philip H. N. Wood points out that taxonomic approaches used in the development of the International Classification of Diseases were found unsatisfactory. "Separate classifications of impairments and handicaps were prepared" and "circulated widely in 1974." The following excerpts from the introductory remarks trace the steps that were to follow: … Responsibility for collating comments and developing definitive proposals was undertaken by Dr. Wood. These were submitted for consideration by the International Conference for the Ninth Revision of the International Classification of Diseases in October 1975. At this juncture the scheme incorporated a supplementary digit to identify disability, and the whole approach was acknowledged as being to a large extent experimental and exploratory. Having considered the classification, the Conference recommended its publication for trial purposes. In 1976, the Twenty-ninth World Health Assembly … approved the publication, for trial purposes, of the supplementary classification of impairments and handicaps as a supplement to, but not as an integral part of the International Classification of Diseases. The present manual, published under this authority, represents a considerable recasting of the detailed proposals submitted to the Ninth Revision Conference. (p. 13) The conceptual scheme in the WHO publication (1980) is organized around four concepts: disease, impairment, disability, and handicap. In Wood's words, these four concepts are defined as follows: Something abnormal occurs within the individual: this may be present at birth or acquired later. A chain of causal circumstances, the "etiology," gives rise to changes in the structure or functioning of the body, the "pathology". Pathological changes may or may not make themselves evident; when they do they are described as "manifestations", which in medical parlance, are usually distinguished as ''symptoms and signs". These features are the components of the medical model of disease,… Someone becomes aware of such an occurrence: in other words, the pathological state is exteriorized. … In behavioral terms, the individual

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Disability in America: Toward a National Agenda for Prevention has become or been made aware that he is unhealthy. His illness heralds recognition of impairments, abnormalities of the body structure and appearance, and of organ or system function, resulting from any cause. Impairments represent disturbances at the organ level. … In the context of health experience, an impairment is any loss or abnormality of psychological, physiological, or anatomical structure or function. The performance or behavior of the individual may be altered as a result of this awareness, either consequentially or cognitively. Common activities may become restricted, and in this way the experience is objectified. Also relevant are psychological responses to the presence of disease, part of so-called illness behavior, and sickness phenomena, the patterning of illness manifested as behavior by the individual in response to the expectations others have of him when he is ill. These experiences represent disabilities, which reflect the consequences of impairments in terms of functional performance and activity by the individual. Disabilities represent disturbances at the level of the person. … In the context of health experience, a disability is any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being. Either the awareness itself, or the altered behavior or performance to which this gives rise, may place the individual at a disadvantage relative to others, thus socializing the experience. This plane reflects the response of society to the individual's experience, be this expressed in attitudes, such as the engendering of stigma, or in behavior, which may include specific instruments such as legislation. These experiences represent handicap, the disadvantages resulting from impairment and disability. … In the context of health experience, a handicap is a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual. (pp. 25-29) The WHO publication includes a narrative section that outlines the history of the undertaking, the purposes, the conceptual framework, and the rationale for classification. It also includes the classifications themselves for impairments (Code I), disabilities (Code D), and handicaps (Code H). ASSESSMENT OF FRAMEWORKS The two frameworks outlined here—which are identified in the literature with Nagi and Wood—have been the subject of comparisons and analyses by several writers (e.g., Duckworth, 1984; Frey, 1984; Granger, 1984). These analyses are generally limited and frequently reveal that certain specifications are not clearly understood. The difference is not only in semantics nor simply that one framework is an extension of the other. There are also

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Disability in America: Toward a National Agenda for Prevention important substantive differences. It is often difficult to communicate conceptual constructs within the same discipline, let alone across varying disciplines and professional fields, which may account for some of the misinterpretations that have been plaguing this area. The remainder of this paper assesses these frameworks in light of important criteria that govern conceptualization, classification, and theory construction. Kaplan (1964) suggests three sets of criteria for assessing frameworks: norms of coherence, norms of correspondence, and pragmatic norms. These criteria will be used as guides, and each framework will be examined individually rather than by a point-counterpoint discussion. Wood's scheme will be examined first. Table A-1 compares the Nagi and Wood taxonomies. An important aspect of a framework's internal coherence is criteria that differentiate among concepts and categories. For Wood, a disease becomes an impairment when it is "exteriorized"; by that he means that "someone becomes aware of such an occurrence. … Most often the individual himself becomes aware of disease manifestations … deviations may be identified of which the 'patient' himself is unaware … as screening programs are extended. … Alternatively, a relative or someone else may draw attention to disease manifestations." By equating impairment with awareness, Wood is saying in effect that impairments do not exist independently of someone's recognition of them. But what about asymptomatic disorders that have not been identified through screening or that go unnoticed by relatives and friends? Moreover, if "illness heralds recognition of impairments," what about impairments that are not associated with active pathology? Why does Wood's definition of impairment—"any loss or abnormality of psychological, physiological, or anatomical structure or function"—fail to make reference to awareness? It seems that this distinction confuses the conditions themselves with an awareness of their presence and the behavioral patterns evoked by such awareness. Wood's criterion for differentiating between impairment and disability is "objectification," which he describes as "the process through which a functional limitation expresses itself as a reality in everyday life, the problem being made objective because the activities of the body are interfered with" (WHO, 1980:28). The term "objective" is the contrast of ''subjective," and every concept has both objective and subjective aspects. For diseases and disorders, indicators of these two aspects are grouped as signs and symptoms, respectively. Similarly, impairments, functional limitations, and disabilities can all be considered from objective or subjective viewpoints. It is not clear that objectification is equated with an individual's awareness of a change in identity when disability takes form. An important question is what do objective and subjective distinctions and awareness have to do with differences between disease and impairment on the one hand and disability on the other? Again, criteria related to the conditions themselves and the levels of

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Disability in America: Toward a National Agenda for Prevention TABLE A-1a Nagi Taxonomy of Disability Element Active Pathology Impairment Functional Limitation Disability Definitions Interruption or interference with normal processes and efforts of the organism to regain normal state. Anatomical, physiological, mental, or emotional abnormalities or loss Limitation in performance at the level of the whole organism or or person. Limitation in performance of socially defined roles and tasks within a sociocultural and physical environment. Differentiating criteria All conditions of active pathology constitute a subclass of impairments which in turn include two other subclasses: (1) residual loss and abnormality after active pathology has been arrested, and (2) congenital loss or abnormality not associated with active pathology. Impairment is a more inclusive concept.         Both impairment and functional limitation involve function; in impairment, reference is to the levels of tissues, organs, and systems; in functional limitation, reference is to the level of the organism or the person as a whole.         Functional limitation refers to organismic performance; disability refers to social performance; disability is a relational concept, whereas the other three are concepts of attributes. Indicators Symptoms and signs including observations; indicators are to be found in attributes of the individual. Symptoms and signs including observations; indicators are to be found in attributes of the individual. Limitations in the various activities of the organism such as walking, climbing, reaching, reasoning, seeing, hearing, etc.; indicators can be grouped into larger categories such as physical, mental, emotional, sensory, communication, etc.; indicators are to be found in attributes of the individual. Limitations in performance of such roles and tasks as related to family, work, community, school, recreation, self-care, etc.; indicators are to be found in the relations on the one hand, and the conditions in the sociocultural and physical environment on the other.

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Disability in America: Toward a National Agenda for Prevention TABLE A-1b Wood Taxonomy of Disability Element Disease Impairment Disability Handicap Definitions Something abnormal within the individual; etiology gives rise to change in structure and functioning of the body. Any loss or abnormality of psychological, physiological, or anatomical structure or function at the organ level. Any restriction or lack of ability to perform an activity in the manner considered normal for a human being. A disadvantage resulting from an impairment or a disability that limits or prevents the fulfillment of a role that is normal depending on age, sex, and sociocultural factors. Differentiating criteria A disease becomes an impairment when "exteriorized," that is, when someone becomes aware of it; impairment is more inclusive than disease because it does not necessarily indicate that disease is present.       Impairment becomes disability when the problem is made "objective because activities of the body are interfered with"; disability refers to performance of the individual as opposed to that of the organ or mechanism.       Handicap is differentiated from disability in that the former is "socialized"; it involves "valuation," which is usually to the disadvantage of the individual; handicap is relative to other people. Indicators Symptoms and signs. Symptoms, signs, and awareness of the individual. A wide range of categories including awareness, family and occupational roles, communication, personal care, locomotor, body disposition, dexterity, situational, skull, and other restrictions. A variety of categories including orientation, physical independence, mobility, occupation, social integration, and economic self-sufficiency.

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Disability in America: Toward a National Agenda for Prevention organization at which they are manifested are confused with awareness and behavioral patterns. Confusion in these verbal definitions of the concepts spills over into the operationalization of the classification system. Disability turns into handicap as it becomes "socialized" in that "(i) some value is attached to departure from a structural, functional, or performance norm, either by the individual himself or by his peers in a group to which he relates; (ii) the valuation is dependent on cultural norms …; [and] (iii) … the valuation is usually to the disadvantage of the affected individual" (WHO, 1980:29). In these distinctions, Wood fails to differentiate between limitations in social performance and the causes for these limitations, that is, between the "what" and the ''why." A concept is concerned with the what—a person is unable to work or is limited in performing a family role. Valuations, stereotyping, discrimination, service and benefits programs, labor market conditions, technological developments, architectural barriers, and other factors in the sociocultural and physical environment are causal influences that can facilitate or inhibit the optimal social performance of which a person is capable. These factors are part of why social performance becomes limited. The relationships between the "what" and the "why" are empirical, in that they are subsumed under testable propositions, rather than definitional, in the sense of being subsumed under a concept. Wood is correct in stating that "it is a fundamental principle … that classification is subordinate to a purpose." However, as Hempel (1963) points out, "classification in empirical science, is subject to the requirement of fruitfulness. The characteristics which serve to define the different types should not merely provide neat pigeonholes to accommodate all the individual cases in the domain of inquiry, but should lend themselves to sound generalizations." These points are clarified further by Kaplan (1964): What makes a concept significant is that the classification it institutes is one into which things fall, as it were, of themselves. It carves at the joints. … [A] significant concept so groups or divides its subject matter that it can enter into many and important true propositions about the subject matter other than those which state the classification itself. Traditionally, such a concept was said to identify a "natural" class rather than an "artificial" one. Its naturalness consists in this, that the attributes it chooses as the basis of classification are significantly related to the attributes conceptualized elsewhere in our thinking. Things are grouped together because they resemble one another. A natural grouping is one which allows the discovery of many more, and more important, resemblances than those originally recognized. Every classification serves some purpose or other. … [I]t is artificial when we cannot do more with it than we first intended. The purpose of scientific classification is to facilitate the fulfillment of any purpose whatever, to disclose the relationships that must be taken into account no matter what.

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Disability in America: Toward a National Agenda for Prevention There are no meaningful resemblances that would justify grouping under the same concept "family role disability" and "occupational role disability" on one hand and "foot control disability'' and "crouching disability" on the other. How can "family role disability" and "occupational role disability" be assessed in the absence of expectations and what Wood refers to as valuations? The enunciation of the categories that make up codes in these areas is in itself a statement of expectations and valuations. These and numerous other examples demonstrate serious problems with the concept of disability as outlined in the WHO framework. Ambivalence is acknowledged about "functional limitations," which were regarded in an earlier draft "as being elements of disability" and were later assimilated with impairments. As part of the impairment grouping, functional limitations are conceptualized at the organ level rather than at the level of the whole organism. In addition, disability includes a mix of social and organismic performance. Thus the framework lacks a coherent and clearly delineated concept of performance at the level of the organism. This represents a major gap because functional limitations conceptualized at this level represent the most crucial link between impairment and social performance. The definition of "handicap" leads the reader to expect major, if not exclusive, emphasis on factors in the sociocultural and physical environment—stereotyping, prejudice, discrimination, employment opportunities, and other kinds of barriers. The closest category to this conception is "social integration," but even there the emphasis is still on the individual's impairment and limitations. In some other categories, classification becomes exclusively that of severity of impairment and limitation in function—for example, restrictions in mobility to one's neighborhood, dwelling, room, or chair. Finally, the categories included under the handicap rubric significantly overlap with some of those under disability, such as in the case of family and occupational roles. Some of the categories included under the handicap concept actually represent summaries of items included under other concepts. Every concept has an "attribute space" (Lazarsfeld, 1972), which comprises its dimensions and indicators or manifestations. When a number of indicators of a particular concept are combined in a typology or a larger category—which is by necessity more abstract—the newly created typology or larger category remains within the attribute space of the same concept. Consider, for example, several categories under "orientation handicap," which is no more than an attempt to combine a number of functional limitations, impairments, and diseases. Furthermore, the attempt to combine several limitations, their severities, compensatory aids, and the help of others is a recipe for a cumbersome classification. The elements of compensatory aids and help from others could have been handled in simpler ways without loss of information or precision. Simplicity without loss is an important norm of coherence.

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Disability in America: Toward a National Agenda for Prevention Another important norm of coherence concerns the way a conceptual scheme is integrated into existing knowledge. This criterion need not be applied in a conservative manner that shuts out real breakthroughs. A new framework may be consistent with existing one(s), it may be different in part, or it may be altogether different. The test of integration serves at least two purposes: (1) it adds to the cumulative process that advances the development of knowledge, and (2) it can help avoid compartmentalization, duplication of effort, and, worse, confusion. Wood's conceptual framework and classification scheme fail to meet this requirement. Such statements as "the confusion … stems largely from the lack of a coherent scheme or conceptual framework" and that the purposes of surveys and studies in determining eligibility for benefits in the United States have been "to identify categories or groups of people fulfilling predetermined criteria; words of this type have, therefore, been concerned more with assignment than with evaluation" do not reflect the status of knowledge at that time. Frameworks existed prior to his initiative, and studies and surveys conducted during and since the 1950s have paid considerable attention to measurement (e.g., Commission on Chronic Illness, 1957; Trussel and Elinson, 1959; Srole et al., 1962; Nagi, 1969). By the mid-1970s, there was much more in the literature, especially in the United States, than can be justifiably dismissed in a short paragraph. A systematic review would probably have helped Wood's scheme by building on existing foundations, avoiding many of the problems identified above, and fitting the results into a fairly well-developed body of knowledge. So far this discussion has focused on conceptualization and classification, definitional distinctions, resemblances among items and categories grouped under particular concepts, and the ways in which the whole framework does or does not fit within existing knowledge. Also of importance are norms of correspondence that refer to how a framework "fits the facts." "Science is fundamentally governed by the reality principle" (Kaplan, 1964). These norms apply to the results of empirical research based on concepts defined and operationalized in the manner outlined in the framework. Such research may be aimed at identifying the antecedents or consequences of the various concepts in the framework. Through the process of inquiry and verification, the adequacy of concepts, classifications, and propositions are put to the tests of correspondence. It is too early to assess Wood's framework in view of these criteria. The application of pragmatic norms would be similarly premature; these pertain to the working of a framework—what it can do to advance scientific developments and guide actions. It is important to note, however, that the problems in coherence identified above do not bode well for the framework to adequately fulfill correspondence or pragmatic criteria. Claims of support by individuals, associations, or other organizations do not confer validity. "It must be kept in mind that the validation of theory—or of any other scientific belief—is not a matter of any official decision, the

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Disability in America: Toward a National Agenda for Prevention deliverance of a solemn judgment" (Kaplan, 1964). It is only through inquiry and evidence that frameworks can prove their worth. The developmental history of this framework, as cited by Wood, raises serious questions about the role of WHO's committees. If the present manual, published by WHO, "represents a considerable recasting [emphasis added] of the detailed proposals submitted to the Ninth Revision Conference," one has to wonder about the ability of the Conference to approve frameworks of concepts and terminology that meet Kaplan's criteria for classification. An unfortunate outcome is reintroducing confusion in concepts and terminology just as researchers, government agencies, and policy analysts have started to make significant gains toward shared concepts and common frames of reference. Attempts to meet norms of coherence in Nagi's framework are embodied in the review of conceptual history, from which the framework evolved, as well as in the conceptual distinctions and clarifications presented in earlier sections of this paper. The literature review places this framework within existing knowledge, and the criteria of differentiation among concepts reveal the logic of its internal structure. A repetition of this discussion here would be unnecessary. Suffice it to say that this framework is consistent with conceptual and definitional discussions that have appeared during the last quarter of a century, including those by economists, historians, physicians, political scientists, and sociologists (e.g., Burk, 1967; Howards et al., 1980; Berkowitz, 1987; DeJong, 1987; Johnson, 1987; Haber, 1988, 1990). It is consistent with concepts used in major national surveys (e.g., Social Security Administration, 1981, 1982) and definitions of work disability by the U.S. Bureau of the Census. Inquiries clarify concepts and theoretical frameworks through successive approximations that involve cycles of operationalization, empirical testing, and further specification. The evolution of this framework has been and continues to be subject to this process of improving correspondence among theory, concepts, and facts. Neither time nor space would allow for a comprehensive survey of studies and results that derived conceptual orientation from this framework.