Documentation for the Workshop / Country Papers : New Zealand

New Zealand Disability Survey

Statistics New Zealand
September 2003

1. Issues associated with collecting information on disability in the Population Census

1.1 Background

Statistics New Zealand aims to ensure that population censuses reflect the wider information needs of government and the community. Prior to each census, Statistics New Zealand consults widely with census data users on what they perceive as their information needs from topics for the upcoming census. These information needs feed into an evaluation process which considers each against a standard set of criteria before a recommendation on content is provided to the Government Statistician. The Government Statistician who makes the final decision on the content of the census

One major feature of the census is the fact that it not only provides a 'snapshot' of the nation at a particular point in time but also, by comparison with earlier censuses, enables us to trace the evolution of our nation over time. Therefore, the desire to provide data that is relevant to our most current information needs has to be balanced against the desire to maintain a significant degree of continuity over time, and the need to minimise respondent burden.

The census is recognised as playing a pivotal role in New Zealand's system of social and economic statistics, however the census is only one of a range of data sources (others include administrative as well as survey data). In some instances, interviewer-administered surveys or administrative data collections may provide better quality information than is able to be collected in the census.
Statistics New Zealand is currently leading work on the development of an integrated social surveys programme to provide regular information on a wide range of topics, in addition to that which is available from the census and administrative sources .

1.2 Census content issues

The census is a self-completed questionnaire and as such there are limits to the size and complexity of the information that can be included. In addition, all census topics compete for space both in terms of respondent burden and cost.

To make it as easy as possible to complete the census forms, encourage maximum participation and thus ensure quality data, restrictions are placed on the size of the questionnaires and the complexity of the questions. Because the entire population in New Zealand on census night is required to complete the questionnaires, largely without assistance, it is not possible to ask complex questions. Nor is it desirable to include topics that will require respondents to access records in order to complete the questionnaires. The nature, and particularly the size, of the census means that a certain amount of time is also required to capture, process and release the data.

In particular, census is not the best source of data if the information required is:

complex or sensitive
needed to determine underlying causes of a trend or event
needed within six months or so of the collection date, or
needed on a regular basis.

1.3 Disability questions in the census

People with disabilities make up a significant part of the New Zealand population. A question on disability was first asked in 1911 and again in the 1916 Census of Population and Dwellings. A more general question on disability was next trialled for the 1981 Census but was not included. Questions on disability were reintroduced into the 1996 and 2001 Censuses.

Disability is a complex concept, which is difficult to measure in a census type format. The definitions of disability are not easy to communicate and are difficult to convey to the entire population in one or two simple questions to all levels of literacy on the census questionnaire.

In 1996 and 2001, the questions were included only to provide a sample frame for a comprehensive follow-up survey on disability. This had been assessed as the most cost-effective method of identifying the target population. Our evaluation of these questions at the last two censuses indicates that they provide at best a very crude measure of disability. There are both false positive (where people wrongly indicate that they have a disability) and false negative (where people wrongly indicate that they do not have a disability) answers to the questions. For example, at the 2001 Census, 38 percent of people who answered on their census form that they had a disability, in fact did not. Of those who said they did not have a disability, 12 percent actually had one. These questions produced information that is inaccurate in itself and had a systematic bias. The net effect was to understate the level of disability, particularly amongst older people and amongst people with mild disabilities. Because of the known quality issues, no data on disability has been published from the census.

No decision on whether another post-censal survey on disability will be undertaken in 2006 has yet been made. This decision will be made after a careful evaluation of the information needs on disability and how these might best be met.

2. New Zealand Disability Survey

2.1 Background

Statistics New Zealand has conducted two national surveys on disability. The first survey was undertaken in 1996/97 and was an important milestone for the disability sector. It was the first time in recent decades that people with disabilities have been identified and counted in official statistics. The survey was repeated in 2001 (with some enhancements) to measure the impact of important policy changes since the 1996/97 survey on the well-being of people with disabilities in New Zealand.

2.2 Objectives

The key objectives of the 2001 Disability Survey were:

To measure the prevalence of disabilities amongst:
- children, adults and older persons at the national and regional levels; and
- Mäori and Pacific peoples at the national level
To provide information on the nature, duration, severity (resource definition) and cause of disability amongst the population with disabilities
To obtain data on the socio-demographic characteristics of the population with disabilities, including their age, sex, ethnicity, marital status, educational qualifications, labour force status, income and household and family circumstances
To compare and contrast information collected on people with disabilities in 2001 with that collected in the 1996/97 Disability Survey.

The secondary objectives were:

To provide information on the types of disability related expenses which are incurred by individuals and their families
To identify the current use of and unmet needs for technical and personal support services, both formal and informal (e.g. home-help, special equipment for transport and accommodation, walking sticks etc) and the reason for the need remaining unmet amongst the population with disabilities.

These objectives were largely the same as those for the 1996/97 survey, with two exceptions. Firstly, the 2001 survey was designed to measure the prevalence of disability among Pacific People in addition to Mäori. And secondly, the 2001 survey included an additional objective, which was to provide information on people with disabilities that could be compared and contrasted with data from the previous survey.

2.3 Concept of disability

In both the 1996/97 and 2001 surveys, a functional concept of disability was used. A person was defined as having a disability if he or she had an activity limitation, resulting from a long-term condition or health problem that had lasted or was expected to last six months or longer. This was determined by responses to a series of questions that assessed difficulty performing certain everyday activities such as, reading the paper, having a conversation with another person or dressing yourself. The answers reflected the respondent's own perception of their situation. The activity limitations were classified as follows:

Physical

Mobility
Agility

Sensory

Seeing
Hearing

Psychiatric and psychological

Intellectual

Other

Speaking
Learning & remembering

2.4 Survey methodology

The survey covered both people living in private households and those living in residential facilities (institutions). Collection of data from both groups was necessary to produce a complete picture of disability in New Zealand.

Private households

Around 40,000 people living in private households were selected to take part in the household component of the survey. The census disability questions were used to help identify people with disabilities to take part in the survey. In addition to including a sample of people who said they had a disability a sample of those who said they did not were included. The reason for including the latter group is that some people who have a disability do not record it in the census. For example, in the 2001 Disability Survey 12 percent of people who reported that they did not have a disability did in fact have one. Many of these people may have less serious disabilities, but as a group they represent a particular segment of the population with disabilities and they should be included in the survey to avoid bias.

The sample selection for the survey took into consideration the need to balance the sample across the country and to include a selection of ages. A major enhancement to the 2001 survey over the previous survey was over-sampling of Mäori and Pacific People so that reliable estimates could be produced for these groups.

Residential facilities

Unlike the household component of the Disability Survey which covered all ages (children, adults and older people), the residential facilities component was confined to people aged 15 years and over. The decision to confine the residential facilities component to adults aged 15 years and over living in residential facilities was made for reasons of cost. Because there are very few children living in residential facilities, obtaining a sample sufficiently large to produce reliable estimates would have been an extremely costly exercise.

The sample for the residential facilities part of the survey included people living in homes for the elderly, those occupying long-stay beds in public or private hospitals and those living in long-stay residential units (with 10 or more people) for people with an intellectual, psychiatric or physical disability. Some types of residential facilities were excluded from the survey. Examples include hospices, acute psychiatric wards, forensic psychiatric wards/hospitals, prisons, public and private short stay beds and boarding houses. The reason for excluding them was the cost and difficulty of getting a list of these types of dwelling, particularly boarding houses, the ethical issues associated with attempting to interview people in distressful situations and the special interview procedures required for facilities like penal institutions.

The exclusion of these facilities from the survey is not considered to have had a significant impact on the overall estimates of disability prevalence, as most of the target population with a disability was covered in the survey population. However, it may have resulted in an underestimation of particular types of disability, such as psychiatric disabilities.

For both phases of the survey, residential facilities and private households, the interviewers were provided with full training, not only on the survey, but also on interviewing people with disabilities. This included a sensitivity training session to ensure that the interviewers were trained on the appropriate terminology to use when interviewing people with disabilities.

2.5 Questionnaires

There were five questionnaires for the Disability Survey - two for adults and two for children living in private households and one for people living in residential facilities.

It was necessary to have five questionnaires because the issues for adults and children with disabilities are very different. Similarly, the issues facing people with disabilities living in the community are different from those facing people living in residential facilities. Also, because of the difficulties in determining whether children have a disability, a different approach was used to that used for adults. This necessitated a different set of screening questions for adults and children.

The following is a summary of the format and the content of the questionnaires:

Adult's Screening Questionnaire

The questions in this questionnaire were designed to determine if respondents aged 15 years and over living in private dwellings had an activity limitation that was expected to last six months or longer. Other questions asked about:

the duration of the limitation
the main condition or health problem that causes the limitation
the cause of the condition (e.g. disease or illness, existed at birth, accident/injury at home or school, motor vehicle accident, a sports accident, or another cause)
the main activity limitation (for people with multiple limitations) (2001 only)

Adult's Content Questionnaire

People identified as having one or more activity limitations in the screening questionnaire were asked a further set of questions to determine how the limitation(s) affected them in everyday life. The questions covered the following areas:

Services and Assistance
The purpose of this section was to obtain information on how the respondents' activity limitation(s) affect their ability to carry out everyday household activities such as preparing meals, shopping, doing light and heavy chores, managing personal finances etc. The responses to these questions provided information on how much support is needed for people with disabilities to live independently. Questions were also asked about the respondents' use of health services and professionals, as well as their use of prescription and non-prescription drugs.

Employment
This section was designed to provide insights into the types of assistance and support needed by people with disabilities to participate in the labour market. The questions provide insights into the barriers faced by people in the labour market.

Education
The intent of this section was to determine the impact of respondents' activity limitations on their educational experience.

Transport
This section addressed the problems faced by people with disabilities in using the local transportation system and the difficulties experienced travelling longer distances by plane, bus, train and car.

Accommodation
This section asked questions about special features the respondent used or needed for entering, leaving and moving about inside their home.

Special Equipment
The purpose of this section was to identify technical aids needed or used by respondents to help them get around and do things on their own. It also asked about special dietary needs.

Economic characteristics
This section was designed to obtain information about government financial help received by respondents because of their condition.

Children's Screening Questionnaire

This questionnaire identified chronic conditions among children living in permanent private dwellings, as well as the use of special aids and limitations experienced by children at home, school or play. The questions were used to determine whether the child has a disability.

Children's Content Questionnaire

Services and assistance
This section obtained information on any special services and medication required by children with disabilities to help them manage everyday activities.

Education
The questions in this section were designed to measure the impact of a child's disability on his/her education and the obstacles faced in obtaining education.

Transport
This section asked about the problems faced by children with disabilities in taking short local trips and in travelling longer distances by plane, bus, train, ferry or car.

Accommodation
This section enquired about special features children with disabilities used or needed for entering, leaving and moving about their home.

Economic Circumstances
The purpose of this section was to obtain information on whether any government financial help was received because of the child's disability.

Residential Care Questionnaire

This questionnaire was very similar to the Adult Screening Questionnaire that was used for interviewing people living in private households, but also included a number of questions on equipment and assistance used. Other questions included in the Adult Content Questionnaire, covering barriers in education, employment, transportation and accommodation were not considered relevant to people living in residential facilities.

2.6 Analysis of the Disability Survey Data

Tabular results from the surveys were published by SNZ in Disability Counts. In addition, following the 2001 Survey, the department produced a series of nine snapshots, which presented information relating to different disability groups (eg people with physical disabilities, sensory disabilities, children with disabilities etc).

A major analytical report 'One in Five', based on results from the 1996/97 Disability Survey was published by the Ministry of Health. A similar report featuring detailed analysis of the 2001 Disability Survey data and where possible, comparisons with the 1996/97 data, is currently being co-ordinated by the ministry.

The survey results show that the prevalence of disability has not changed significantly between 1996/97 and 2001. This is true for different age groups and also for the Mäori population. The pattern of different disability types has also stayed broadly the same over the five year period. The surveys show that around four in ten disabled people living in households receive help with everyday activities. One in eight have an unmet need for special equipment or health services.

The 1996/97 and 2001 Disability Surveys provide a rich database on people with disabilities and their characteristics and needs. Data from the surveys can be used to:

examine the prevalence of disability, and characteristics of people with disabilities
analyse access to services and unmet needs for support and equipment amongst people with disabilities
compare the characteristics of people with disabilities with those of non-disabled people
analyse the prevalence of disability amongst Mäori and Pacific Peoples (2001 only)
analyse the characteristics of people with disabilities living in institutions and compare them with those living in households
analyse changes in the numbers and proportions of people with disabilities, their characteristics and their needs between 1996/97 and 2001.

Data from the surveys is not sufficiently reliable to:

analyse the numbers, characteristics and needs of the disabled population at a detailed regional level, such as District Health Boards. The finest level of regional breakdown possible is the 4 Regional Health Authorities.
analyse small sub-groups of the disabled population, such as deaf people and blind people
provide reliable information about prevalence of conditions such as arthritis, Alzheimer's disease, Parkinson's disease (the survey is based on activity limitations and not type of disease, although people who are identified as having a disability are asked what the underlying cause of the disability is).

The surveys provide limited or no data on:

the participation of people with disabilities in different areas of life e.g. education and training, social activities, recreation and culture, voluntary activities etc
outcomes amongst people with disabilities
carers of people with disabilities and their characteristics and needs
service providers
discrimination against people with disabilities.

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