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Estimating Population with Disabilities in Hong Kong:For What and Whose Purposes?

Joseph Kwok

Associate Dean, Faculty of Humanities and Social Sciences
City University of Hong Kong
Hong Kong

Abstract Hong Kong has three major sets of statistics of people with disabilities, namely: statistics of the Central Registry for Rehabilitation, statistics of the Rehabilitation Programme Plan, and statistics from General Household Surveys. The first two are compiled and managed by the Health and Welfare Bureau and the last one by the Census and Statistics Department of the Government of Hong Kong Special Administrative Region. This paper discusses and compares these three sets of data. The relevance of these three sets of data to the planning of rehabilitation services in Hong Kong is given in the discussion section.

Central Registry for Rehabilitation

The Central Registry for Rehabilitation (CRR) was set up in 1983 by a government policy bureau to collect and compile information on people with disabilities for purposes of planning and delivery of rehabilitation services and research. CRR covers eight categories of disabilities, same as those recognizes by Rehabilitation Programme Plan (RPP).

The CRR collects information on people with disabilities on a voluntary basis through relevant government departments and NGOs upon their first contact with a disabled person. To simplify disability certification and to encourage public acceptance, CRR issues a registration card to CRR registrants. The registration card is accepted by increasing number of schemes/organizations, both in private and NGO sectors, as an identity proof for price concessions and privileged services.

In spite of the efforts to encourage registration, the reliability of the CRR data set has always been a major problem. First, the 1992 Green Paper openly admitted the problem of under-reporting (Working Party on Rehabilitation Policies and Services, 1992). Second, the information contained in the Central Registry for Rehabilitation has been found to be seriously out-dated. In a territory-wide research, telephone inquiries were conducted on a sample of registrants to find out whether they could be reached. It was reported that over 70 percent of the names given had either moved away, died or could not be located (Working Group on Research for International Year of the Family, 1994, p.31).

Still, CRR statistics is being used as a major reference for purposes of policy and services development.

As of March 2001, there were 121,966 registrants in CRR. Among them, 108,958 (89.4 percent) had single disability, 11,124 (9.1 percent) had two types of disability, and 1,884 (1.5 percent) had more than 2 types of disabilities. The distribution of registrants by number of registrations and types of disabilities is given below.

Table 1 Distribution of registrations by number of registrations by and types of disabilities
Types of disability Number of registrations % of total CRR registrations % of total Hong Kong population (6,796,700)
Hearing impairment 12,699 9.2 0.19
Visual impairment 13,500 9.8 0.20
Physical handicap 58,037 42.4 0.85
Speech impairment 2,072 1.5 0.03
Mental handicap 29,048 21.2 0.43
Mental illness 15,089 11.0 0.22
Autism 1,922 1.4 0.03
Visceral disability 4,785 3.5 0.07
Total 137,152 100.0 2.02

Source: Central Registry for Rehabilitation, 2001.

Note: People with multiple disabilities are registered under more than one type of disability.

Table 2 Number of registrations by age group and by sex
Age group Male Female Total
0-20 12,749 7,162 19,911
21-39 18,012 13,657 31,669
40-59 19,225 12,413 31,638
60 and above 26,521 27,374 53,895
Total 76,507 60,606 137,113

Source: Central Registry for Rehabilitation, 2001.

Note: People with multiple disabilities are registered under more than one type of disability.

The General Household Survey Institutional Survey of Census and Statistics Department

The Census and Statistics Department collected selected disability prevalence rates during the 1976 Population By-census and the 1981 Population Census. Because of the limitations caused by enumerators to provide information, complexity of the exercise and difficulties in definition and identification, the information collected was believed to suffer from serious under-reporting. As a remedy, the Census and Statistics Department (CSD) incorporated a territorywide survey on persons with disabilities and chronic diseases, as a special topic enquiry, into its regular General Household Survey (GHS) (Census and Statistics Department, 2001).

The Survey Method

The GHS is a sample survey conducted by CSD on a regular basis primarily to collect data on concerning labour force, plus a supplementary part on special topics required by other departments and policy bureaux. The GHS sample covers all Hong Kong land-based non-institutional population.

The special topic survey of the GHS collected data from PWDs living in domestic households extended over the entire year of 2000 in order to obtain a sufficiently large sample of people of different disabilities. The final random sample size was 44,000 households (about 2 percent of all households in Hong Kong), with a response rate of 90 percent.

A separate institutional survey was conducted in the same year, covering those resided in social welfare institutions, long-stay care hospitals and rehabilitation centers. A two-stage stratified disproportionate sampling design was employed. The final random sample size was 70 institutions and about 1,400 respondents, with a response rate of 90 percent.

In both types of survey, well-trained and experienced interviewers were employed to conduct face-to-face interviews. The following data were collected: (a) type disability, (b) degree of severity, (c) impact of disability on different aspects of life, (d) primary carer and caring services required, and (e) transportation.

Coverage and definition of disability

The special survey adopted a different approach in defining disability from that of the CRR. It defined PWD as those who (i) had been diagnosed by qualified health personnel (such as practitioners of Western medicine and Chinese medicine) as having one or more of the following 7 conditions; or (ii) had perceived themselves as having one or more of the first 4 of the following 7 conditions which had lasted, or were likely to last, for a period of 6 months or more at the time of interview. The seven conditions are further tested by the following indicators to confirm their existence as well as the degree of severity:

Restriction in body movement: confirmed by medical diagnosis, or self reporting as having long-term difficulty in movement of upper/lower limb or other parts of the body; required wheelchair or similar assistive device, had used artificial limbs, needed the help of others to carry a heavy object, grasp a small object and walk up/down a flight of stairs.

Seeing difficulty: confirmed by medical diagnosis, or self reporting as having longterm difficulty in seeing with one eye or both eyes with or without correcting glasses; unable to see at all, required a specialized visual aid, no required a specialized visual aid.

Hearing difficulty: confirmed by medical diagnosis, or self reporting as having longterm difficulty in hearing; unable to hear all, required a specialized hearing aid, not required a specialized hearing aid.

Speech difficulty: confirmed by medical diagnosis, or self reporting as having longterm difficulty in speaking or being understood by others; unable to speak at all, required a specialized aid, not required a specialized aid.

Mental illness: confirmed by medical diagnosis (including ex-mentally ill) Autism: confirmed by medical diagnosis

Mental handicap: confirmed by medical diagnosis.

Limitations of the GHS survey

The GHS survey is subject to at least two limitations: (a) self-reporting or subjective answers may give wrong information, (b) sensitivity or lack of awareness of certain disability conditions leading to under-reporting.

Under-estimation in Respect of Persons with Mental Handicap in the GHS Survey

When the survey findings on the number of mentally handicapped persons are compared with that of the CRR, the survey findings showed significant under-estimations. As a result CSD made use of statistical distribution assumptions derived from CRR and GHS and Institutional survey on proportions of pre-schoolers likely to have mental retardation, proportions between students and non-students with mental handicap, and proportions between economically active and non-active persons with mental handicap. Based on these assumptions, CSD estimates that the number of persons with mental handicap is between 62,000 (excluding pre-schoolers) to 87,000 (including pre-schoolers). Because of the crudeness of the estimates for people with mental handicap, CSD does not include them in the statistical tables.

For the purpose of this paper, the crude figure of 87,000 as supplied by CSD is used.

Estimates of people with disabilities and their key statistics
Table 3 Estimated number of persons with disabilities by CSD
Types of disability No. of persons As (including those with more than one disability) % of total Hong Kong population(6,796,700)
Restriction in body movement 103,500 1.52
Seeing difficulty 73,900 1.09
Hearing difficulty 69,700 1.03
Speech difficulty 18,500 0.27
Mental handicap 87,000 1.28
Mental illness 50,500 0.74
Autism 3,000 0.04
Total 406,100 5.98

Source: Census and Statistics Department, 2001; Table 5.1a and Appendix 3C.

Tables 4 to 8 below give key demographic statistics of the PWD with single or multiple disabilities covering those with restriction in body movement, seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism, but excluding mental retardation.

Table 4 Persons with disabilities (those with restriction in body movement, seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism, but excluding mental retardation) by age/sex
Age group/sex No. of persons(1000) All persons with disabilities@ Total population
% Rate* %
Age group<15 9.0 3.3 0.8 17.2
15-29 13.2 4.9 0.9 20.7
30-39 22.1 8.2 1.7 19.2
40-49 37.7 14.0 3.1 17.8
50-59 35.0 13.0 5.1 10.0
>60 152.5 56.6 15.0 15.0
Sex Male 126.1 46.8 3.8 48.6
Female 143.4 53.2 4.1 51.4
Overall 269.5 100.0 4.0 100.0

Source: Census and Statistics Department, 2001; Table 5.1b.

Notes:

@ A person might have more than one selected type of disability and hence the overall number of persons with disabilities is smaller than the sum of the number of persons with individual types of disability.

* As a percentage of all persons in the respective age/sex groups. For example, among all persons aged below 15, 0.8 percent were persons with disabilities.

Some estimates are based on only a small number of observations and thus should be interpreted with caution.

Table 5 Persons with disabilities (those with restriction in body movement, seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism, but excluding mental retardation) by marital status/educational attainment
Marital status / Educational attainment All persons with disabilities* Total population
No. of persons(1000) % %
Marital status Never married 52.5 19.5 43.0
Married 138.6 51.4 49.9
Widowed/separated/ divorced 78.4 29.1 7.1
Educational attainment No schooling/ kindergarten 80.2 29.8 13.0
Primary 107.9 40.0 26.9
Secondary/matriculation 68.3 25.3 45.4
Tertiary- non-degree 6.4 2.4 5.7
Tertiary- degree 6.7 2.5 9.0
Total 269.5 100.0 100.0

Source: Census and Statistics Department, 2001; Table 5.1c.

Notes:

* A person might have more than one selected type of disability and hence the overall number of persons with disabilities is smaller than the sum of the number of persons with individual types of disability.

Some estimates are based on only a small number of observations and thus should be interpreted with caution.

Table 6 Persons with disability (those with restriction in body movement, seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism, but excluding mental retardation) by age/activity status
Age group / activity status All persons with disabilities@ Total population
No. of persons(1000) %* %^
Aged below 15 9.0 3.3 17.2
Aged 15 and over 260.5 96.7 82.8
Economically active 59.7 (22.9) (60.5)
Economically inactive 200.8 (77.1) (39.5)
Retired persons 131.5 (50.5) (14.7)
Home-makers 25.1 (9.7) (13.9)
Students 3.1 (1.2) (8.3)
Others 41.1 (15.8) (2.5)
Total 269.5 100.0 100.0

Source: Census and Statistics Department, 2001; Table 5.1f.

Notes:

@ A person might have more than one selected type of disability and hence the overall number of persons with disabilities is smaller than the sum of the number of persons with individual types of disability.

* Figures in brackets represent the percentages in respect of all persons aged 15 and over with the respective types of disability.

^ Figures in brackets represent the percentages in respect of all persons aged 15 and over.

Some estimates are based on only a small number of observations and thus should be interpreted with caution.

Table 7 Employed persons with disabilities (those with restriction in body movement,seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism,but excluding mental retardation) by single disability/multiple disabilities
Selected type of disability No. of persons with single disability(1000) No. of persons with multiple disability(1000) Total no. of persons(1000) As % of the total employed population
Restriction in body movement 9.7(63.7) 5.6(36.3) 15.3(100.0) 0.5
Seeing difficulty 5.7(59.6) 3.9(40.4) 9.6(100.0) 0.3
Hearing disfficulty 9.2(58.6) 6.5(41.4) 15.7(100.0) 0.5
Speech difficulty 0.4(16.9) 2.1(83.1) 2.6(100.0) 0.1
Mental illness 9.3(75.4) 3.0(24.6) 12.4(100.0) 0.4
Autism 0.4(71.1) 0.2(28.9) 0.5(100.0) #
All persons with disabilities (excluding mentally handicapped persons)* 34.8(66.3) 17.7(33.7) 52.5(100.0) 1.6

Source: Census and Statistics Department, 2001; Table 5.2a.

Notes:

* An employed person might have more than one selected type of disability and hence the overall number of employed persons with disabilities is smaller than the sum of the number of employed persons with individual types of disability.

Figures in brackets represent the percentages in respect of all employed persons with the corresponding types of disability.

Some estimates are based on only a small number of observations and thus should be interpreted with caution.

Table 8 Employed persons with disabilities (those with restriction in body movement,seeing difficulty, hearing difficulty, speech difficulty, mental illness, autism,but excluding mental retardation) by age/sex
Age group / sex All employed persons with disabilities (excluding handicapped persons)* Total employed population
No. of persons(1000) % %
Age group
15 - 29
4.5 8.6 25.0
30 - 39 11.0 21.0 31.7
40 - 49 17.3 32.9 27.0
50 - 59 13.8 26.3 12.7
>60 5.9 11.2 3.5
Median age (years) 46 37
Sex
Male
34.1 64.9 57.5
Female 18.4 35.1 42.5
Total 52.5 100.0 100.0

Source: Census and Statistics Department, 2001; Table 5.2b.

Notes:

* An employed person might have more than one selected type of disability and hence the overall number of employed persons with disabilities is smaller than the sum of the number of employed persons with individual types of disability.

Some estimates are based on only a small number of observations and thus should be interpreted with caution.

Owing to the small number of sample observations in respect of employed persons with autism as identified in the survey, the estimates pertaining to their demographic and socio-economic profiles were subject to relatively large sampling error. They were therefore not presented in this report in consideration of their limited precision.

Prevalence Rates Adopted by the Government Rehabilitation Progremme Plan

The prevalence rates of the number of PWD as adopted by the Government Rehabilitation Programme Plan are derived from a range of data sources, including that of CRR, clinical records, prevalence rates as adopted by western countries, local surveys, and etc. (Health and Welfare Bureau, 1999). The prevalence rates are presented in the following tables.

Table 9 Estimated Number of Autistic Persons
Age Group (Year : Month) 1998 1999 2000 2001 2002
0:0 - 15:11 1,238 1,240 1,235 1,23 1,230
16:0 or above 5,421 5,529 5,625 5,72 5,810
Total 6,659 6,769 6,860 6,95 7,040

Source: Health and Welfare Bureau, 1999; Table 5.2

Table 10 Estimated Number of Mentally Handicapped Persons
Degree of Mental Handicap 1998 1999 2000 2001 2002
Mild 113,210 115,072 116,620 118,168 119,684
Moderate 13,318 13,538 13,720 13,902 14,080
Severe 4,662 4,738 4,802 4,866 4,928
Profound 1,998 2,030 2,058 2,086 2,112
Total 133,188 135.378 137,200 139,022 140,804

Source: Health and Welfare Bureau, 1999; Table 7.1.

Table 11 Prevalence of Hearing Impairment
Age Group (Year : Month) Prevalence by Age Group (per 10 000 persons)
Profound Severe Moderate/Mild
0:0 - 5:11 1.0567 2.1675 3.0749
6:0 - 11:11 3.8798 8.5696 21.4834
12:0 - 17:11 5.9916 11.6121 37.3891
18:0 - 59:11 8.2752 5.9388 39.4298
60:0 or above 20.6288 17.5689 77.1491

Source: Health and Welfare Bureau, 1999; Table 6.1.

Table 12 Estimated Number of Hearing Impaired Persons
Degree of Hearing Impairment 1998 1999 2000 2001 2002
Profound 6,030 6,146 6,251 6,358 6,455
Severe 5,281 5,376 5,453 5,532 5,603
Moderate/Mild 27,238 27,745 28,198 28,665 29,088
Total 38,549 39,267 39,902 40,555 41,146

Source: Health and Welfare Bureau, 1999; Table 6.2.

Table 13 Estimated Number of Mentally Ill Persons Requiring Rehabilitation Services between 1998 and 2002
Form of Mental Illness 1998 1999 2000 2001 2002
Functional Psychoses 10,137 10,308 10,455 10,602 10,744
Affective Psychoses 13,050 13,299 13,513 13,718 13,908
Organic Psychoses 33,960 35,160 36,290 37,500 38,630
Neuroses 11,620 11,859 12,070 12,279 12,474
Others 4,769 4,871 4,961 5,052 5,136
Child and Adolescent 15,131 15,187 15,166 15,123 15,113
Total 88,667 90,684 92,455 94,274 96,005

Source: Health and Welfare Bureau, 1999; Table 8.2.

Table 14 Prevalence of Physical Handicap and Estimated Number of Physically Handicapped Persons
Age Group(Year : Month) Prevalence by Age Group(per 10,000 persons) Estimated Number of Physically Handicapped Persons
1998 1999 2000 2001 2002
0:0 - 5:11 3.1384 139 139 137 134 134
6:0 - 11:11 34.3424 1,622 1,653 1,666 1,659 1,644
12:0 - 17:11 54.0902 2,650 2,654 2,619 2,605 2,602
18:0 - 59:11 52.6263 22,715 23,126 23,549 23,981 24,382
60:0 or above 444.8701 41,724 42,748 43,642 44,558 45,328
Total 68,850 70,320 71,613 72,937 74,090

Source: Health and Welfare Bureau, 1999; Table 9.1.

Table 15 Prevalence of Visual Impairment
Age Group (Year : Month) Prevalence Rate by Age Group (per 10 000 persons)
Total Blindness Severe Low Vision Mild / Moderate Low Vision
0:0 - 5:11 0.1580 40 60
6:0 - 11:11 0.9593 40 60
12:0 - 17:11 1.8156 40 60
18:0 - 59:11 2.7621 40 60
60:0 or above 55.9055 40 60
Table 16 Estimated Number of Visually Impaired Persons
Degree of Visual Impairment 1998 1999 2000 2001 2002
Total Blindness 6,577 6,728 6,862 6,999 7,116
Severe Low Vision 26,638 27,076 27,440 27,804 28,161
Mild/Moderate Low Vision 39,956 40,613 41,160 41,706 42,241
Total 73,171 74,417 75,462 76,509 77,518

Source: Health and Welfare Bureau, 1999; Table 11.2.

Table 17 Number of persons by types of disability from RPP administrative estimates for Year 2001
Type of disability No. of persons(including those with more than one disability) As percent of total population in Hong Kong (,796,700)
Hearing impairment 40,555 0.60
Visual impairment 76,509 1.13
Mentally handicap 139,022 2.05
Physical handicapped 72,937 1.07
Mentally illness (those requiring rehabilitation services) 94,274 1.39
Autism 6,951 0.10
Total 430,248 6.33

Source: Health and Welfare Bureau, 1999.

A Crude Comparison Between the Estimates of CSD and RPP The table below gives a crude comparison between the estimates of CSD and RPP. The comparison must be interpreted with caution as the two systems adopt different definitions for various categories of disability, and also different statistical assumptions.

Table 18 A crude comparison between the estimates of PWD as percentage of total Hong Kong population (6.796,700) given by Census and Statistics Department and those given by Rehabilitation Program Plan
CSD Estimates As % of total population in Hong Kong RPP Estimates As % of total population in Hong Kong
Restriction in body movement: 1.52 Physical handicap: 1.07
Seeing difficulty: 1.09 Visual impairment: 1.13
Hearing difficulty: 1.03 Hearing impairment: 0.60
Speech difficulty: 0.27 Not available
Mental handicap: 1.28 Mentally handicap: 2.05
Mental illness: 0.74 Mentally illness: 1.39
Autism: 0.04 Autism: 0.10
Total: 5.98 Total: 6.33

Source: Health and Welfare Bureau, 1999; and Census and Statistics Department, 2001.

Note: The definitions used by the two sets of estimates are not identical. Interpretations of the comparisons should be made with caution.

Discussion

The reliability of estimates of population with disabilities is an important factor affecting both long planning projections, particularly in areas of infrastructure and human resources development for rehabilitation services. In Hong Kong, the use of waiting lists of rehabilitation services as basis for long-term estimates may not be entirely useful, because the number of people on waiting lists may be affected by a change in service paradigm and in other service and caring systems, as well as a change in societal conditions. The use of prevalence rates as generally reported in other western countries could serve no more than a reference. The use of Census figures is constrained by the responses limitations as well its non-clinical approach in definition. Therefore, in spite of the availability of seemingly sophisticated sets of population estimates of people with disabilities in Hong Kong, the lack of reliable population planning data is not contributing to useful long term planning exercises. Such limitations are particularly challenging for planning of specialized services, which require substantial investment in infrastructure and specialists human resources development. Because of the limitations, we may encounter acute situations where there would be a substantial wrong match of supply and demand of specialized rehabilitations. At the same time, Hong Kong is facing at least two major transitions, which would affect fundamentally rehabilitation long term planning exercises. The first transition is from "big government, small society" to "small government, big society" in meeting the needs of its people. In more concrete terms, the share of GOs and NGOs (which are now heavily relying on public revenue) in funding and management of rehabilitation services would gradually be reduced whereas that of the private sector would increase. The second transition is the competition from services offered by organizations from neighboring cities, which are attracting more and more people from Hong Kong moving across the border. This is a typical example of a more flexible flow of people, money and goods under the process of globalization. Though in this situation, the process moving fast towards an integration of all systems of the Peal Delta Area in Southern China, while holding on only to the fundamental pillar of the Hong Kong SAR Basic Law, i.e. "One Country Two systems". All these changes would greatly affect the population characteristics of Hong Kong.

Now that we cannot rely on our statistical estimates, the approach of World Health Organization in defining disability would offer some insight to our discussion. Towards the end of 1990's, WHO's 1980 classifications for disability and handicap have become less popular. They are criticized as being too focused on the negative aspects and causing confusion in general use of the language rather than improving information dissemination. Responding to the criticisms, WHO published the ICIDH-2 final version (WHO, 1999) with a new title, "International Classification of Functioning and Disabilities". The revised classification tool uses functioning as an umbrella term for all body functions, activities and participation; and disability as an umbrella term for impairments, activity limitations or participation restrictions. These terms all have their specific meaning in the WHO classification system. The WHO Assembly approved the final version in May 2001 and gave it new acronym, ICF (WHO, 22 May 2001). The ICF has been confirmed by pilot studies that it can serve usefully as a statistical, research, clinical, social policy and educational tool.

The conceptual insights offered by WHO for the two pillar concepts, functioning and disability, suggest that our planning paradigm should move away from disability based specifics, and towards activity, participation as well as the associated limitations and restrictions. This shift of planning paradigm would enhance our abilities and capacities to cope with future possible uncertainties and limitations of our statistical estimates. The planning process would then have a more open framework, which could respond with the greatest freedom and speed of change in dealing with unforeseen new situations. Therefore, based on the assumption that the least specialized and exclusive of a service the more degree of freedom it will have, mainstreaming of rehabilitation services or failing that, consolidation of a wide range of small, specialized services into large planning clusters would be a more reasonable approach. Such an approach is also recommendable for human resources planning, with generalists training as basic qualifying requirements to be supported by life long professional training. Professional and institutional services of a comprehensive range of services within planning clusters should be integrated together to deliver seamless care to people with disabilities and their families. These service clusters should in turn maintain a seamless link with both formal and informal community based caring systems, so that people with disabilities and their families would play a partnership role in planning, assessing and monitoring of the whole range of support services.

Having said the above, population estimates of people with disabilities, particularly trend estimates, still serve important functions in shaping the inclusive role of mainstream services through public education and legislation. The Hong Kong Census figures have already shed very useful light on the degree of marginalization of people with disabilities in areas of education and employment, which lack far beyond the mainstream population. These figures already speak for themselves, and also call for concrete affirmative action from government to remedy the disadvantaged situations. What we need to be cautious about is that such Census estimates are not entirely useful for the planning of future rehabilitation services.

References

  • Census and Statistics Department (2001) Social data collected via the general household survey, special topics report no. 28, persons with disabilities and chronic illness. Hong Kong: Printing Department, HKSAR.
  • Health and Welfare Bureau (1999) Hong Kong Rehabilitation Programme Plan (1998-99 to 2002-03):Towards a New Rehabilitation Era.
    http://www.info.gov.hk/hwb/english/WHATSNEW/RPP/TOC.HTMl
  • Working Group on Research for International Year of the Family (1994) Role of the family in community care. Hong Kong: Hong Kong Council of Social Service.
  • Working Party on Rehabilitation Policies and Services (1992) Green Paper on Equal Opportunities and Full Participation: A Better Tomorrow for All. Hong Kong: Government Printer.
  • WHO (1980) International Classification of Impairments, Disabilities and Handicaps: A Manual of Classification Relating to the Consequences of Disease. Geneva: WHO.
  • WHO (1999) ICIDH-2: International Classification of Functioning and Disability Beta-2 Draft. Geneva:WHO. http://www.who.int/icidh/
  • WHO (22 May 2001) Outcome of the Fifty-Fourth World Health Assembly. Paragraph 10.
    http://www.who.int/wha-1998/IntWhaEb/intro.html