|Documentation for the Workshop /
Country Papers : New Zealand
Survey and census sources of national disability data
Country: New Zealand
1. Overview of survey or census
- Title of survey or census - New Zealand
- Date of latest data collection - 2001
- Periodicity of survey or census - ad hoc
- Contact person(s) for the survey/census - Denise Brown, Chief Analyst
Social Statistics, PO Box 2922, Wellington, New Zealand; denise.brown @ stats.govt.nz,
phone 64 04 495 4600; www.stats.govt.nz
2. Brief summary of survey or census
- Describe what information on disability is collected
- nature, duration, cause and severity of disability, underlying condition, main
disability (for those with multiple disabilities)
- characteristics of people with disabilities e.g age, sex, ethnicity, marital status,
labour force status, highest educational qualification etc
- access to support services and special equipment, including unmet needs.
- What uses are made of the data and who are the users?
NGOs in the disability sector use the data for advocacy. Government departments
use the data to inform policy development and service delivery, and to monitor the
government's disability strategy.
- Were users involved in deciding what information to collect?
A stakeholders committee comprising representatives from government departments
(education, health, social development, labour, Maori development etc) and the disability
sector assisted in defining the survey objectives and information needs.
- What definition of disability was used?
A functional concept of disability was used.
"Any restriction or lack (resulting from impairment) of ability to perform an
activity in the manner or within the range considered normal for a human being."
Using this concept, a disability was defined as any limitation in activity resulting from
a long-term health condition or problem. People were not considered as having a disability
if an assistive device (eg a hearing aid) completely eliminated their limitation. A
concept of time was an additional filter; the disability must have lasted or be expected
to last for six months or longer.
- Were data collected and compiled according to international standards or
national classifications and definitions? (e.g.ICIDH or ICF)
Data were collected and compiled according to the ICIDH.
3. Scope of survey or census
- Describe the population covered in the survey (age, private dwelling
population, institutionalised population, etc.)
The survey covered children, adults and older people living in private dwellings and group
homes and people aged 15 years and over living in residential facilities.
4. Coverage and sampling
- Coverage of survey or census (how well was the scope achieved)
The survey undercovered the target population, as it excluded
- people living in off-shore islands and remote locations inaccessible by private car
because of the high cost of sending interviewers to these places; and
- selected types of non-private dwellings, such as hospices and acute psychiatric wards,
forensic psychiatric wards, prisons, boarding houses etc.
The exclusions are not considered to have a significant impact on estimates of the total
prevalence of disability.
- Sample frame(s) (sample size? Sample frame based on lists, area,
There were separate frames for private households and residential facilities
(institutions). The sample frame for private households was the Population Census. Two
disability questions were included in the census to help identify people with disabilities
to take part in the survey. As well as drawing a sample of census respondents who said
they had a disability, a sample was drawn from those who said they did not. The reason for
including the latter group is that testing and previous surveys have shown that some
people who have a disability do not record it in the census.
The sample-frame for residential facilities was a two-stage frame. The frame for the first
stage was a list of all long-stay units (with 10 or more people) for people with an
intellectual, psychiatric or physical disability, homes for the elderly and public and
private hospitals with long-stay beds. The frame for the second stage was a list of all
eligible residents living in sampled facilities. The administrator of each facility
provided the list.
5. Are there other data sources which you use to benchmark your survey results? (e.g.
previous surveys to compare with? what evaluations did you make of the results?)
The 1996/97 Disability Survey was used to benchmark the results of the 2001 Disability
6. Response and non-response
- What was the response rate?
The achieved response for the household component of the 2001 Disability Survey was 73
percent, and 90 percent for the facilities component.
- Did you evaluate the non-response? (e.g. break it up into full and
partial? impact of non-response? follow-up studies? imputations for missing items?)
Unit non-response was accounted for in the weighting methodology. Item non-response for
some variables for respondents living in private dwellings was accounted for by imputing
their census records.
7. Data collection (Attach or mail us a copy of your questionnaire)
- Manner of collection (face-to-face interviews, self-administered
questionnaire, telephone, other?)
About three-quarters of household interviews for the 2001 Disability Survey were conducted
using Computer Assisted Telephone Interviewing (CATI). Where respondents could not be
interviewed by phone, such as in the case of a profoundly deaf person or in the case of a
person living in a household with no access to a phone, the interview was conducted in
person (face-to-face). Interviews of respondents living in residential facilities
(institutions) were conducted in person by a trained interviewer.
- Type of respondent (who replied? The disabled person or proxy for the
Self and proxy responses were accepted for respondents living in residential facilities.
Proxy response (from a knowledgeable adult) was the main method of collection for
children. For adults living in private households, proxy response was only accepted where
the selected respondent was not capable of answering for him or herself.
- Format of questions (how many questions? pre-coded standardised?)
For respondents living in private households, the survey questions were split into two
questionnaires. The screening questionnaire established whether the respondent had any
disabilities and the nature, duration, cause and underlying condition. The content
questionnaire was only asked of respondents who were established as having a disability in
the screening questionnaire. The content questionnaire covered topics such as, services
and assistance, employment, education, transport accommodation, special equipment and
economic characteristics. Separate screening and content questionnaires were developed for
adults and children. Only one questionnaire was administered to respondents living in
residential facilities. It incorporated the screening questions administered to adults
living in households, and some questions on equipment and assistance used.
- List the languages used in the survey or census
The questionnaires were available in two languages: English and Samoan. In
addition, interviewers who could conduct interviews in Maori and NZ sign language
interpreters were available if required. Most interviews were conducted in English.
8. Measurement error
- Which special data collection procedures were undertaken to reduce measurement
error (e.g. pilot testing of questions and questionnaire? training of
interviewers? detailed coding instructions? follow-up of non response by specialist
Centralised Computer Assisted Interviewing (CATI) enabled CATI supervisors to monitor
interviewers calls and to review the work of individual interviewers. The CATI
interviewers made up to six calls to contact someone in the household or to contact the
respondent. If someone at the household was contacted, the best time to call the
respondent was established. Pen and paper interviewers (PAPI) made up to three attempts to
talk with someone at the respondent's address and a further three attempts to complete an
interview with the respondent. Both CATI and PAPI interviewers attempted to contact
selected survey respondents who had moved from their usual residence on Census night. The
use of an electronic questionnaire (EQ) for the majority of household interviews ensured
that interviewers could not skip a question without putting an answer in, and ensured the
routing was correct. The EQ also ensured that answers made sense, with built-in edits. The
questionnaire used for the Residential Facilities was simpler than that used for
households, and extensive use was made of family and staff proxies for respondents unable
to answer for themselves due to memory loss or other conditions.
9. Highlights of the strengths and limitations of survey or census
Strengths: (e.g. a very detailed survey; sound sample design; use of
international standard concept and classifications, etc.)
The major strengths of the survey are that it provides the only comprehensive and reliable
statistical information on the nature and extent of disability in New Zealand and the
barriers faced by people with disabilities in their day-to-day lives. The survey content
was developed with major input from the disability sector, and is therefore relevant and
appropriate to their needs. The questions were cognitively tested and the survey
instrument and field procedures tested in a pilot survey. Data from the 2001 Survey is
comparable with that from the 1996/97 Survey. Oversampling of the Maori and Pacific
populations in the 2001 Disability Survey increased the reliability of estimates for these
Limitations: (e.g. high relative standard error for small population
groups/geographic areas; respondent overload due to length of questionnaire; lack of
consistency or survey items across surveys, etc.)
A major limitation of the survey is that it underestimates intellectual and psychiatric
disability, a consequence of the fact that the survey excludes people living in some types
of residential facilities, such as prisons and acute psychiatric wards. A further
limitation is inability to produce estimates for small areas and small population groups.
Because the survey is ad hoc, there is no guarantee that it will be repeated in the
10. List published sources on disability statistics
Disability Counts, Statistics New Zealand, March 1998
Disability in New Zealand: Overview of the 1996/97 Surveys, Health Funding
Authority and Ministry of Health.
Disability Counts 2001, Statistics New Zealand, May 2002
Disability Surveys Snapshots:
- Key facts
- Pacific Peoples
- People in Residential Care
- Sensory Disabilities
- Physical Disabilities
- Intellectual Disabilities
- Psychiatric and Psychological Disabilities
(The snapshots are published on the Statistics New Zealand's website: www.stats.govt.nz)
See also: New Zealand Disability Survey contributed
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