Scottish Government

Social Focus on Disability 2004

Appendix 2: Surveys and Comparisons of Results

The Scottish Household Survey

The information used in this publication comes primarily from the Scottish Household Survey (SHS) and relates to questions asked in the 2001/2002 survey years. Information on disability is sought in two separate parts of the survey: questions are asked of the highest income householder (HIH) about all members of the household (including dependent children), and a random adult in the household is also asked about their own experience of disability and ill health.

The highest income householder (HIH) is asked by the interviewer:

'Could you tell me whether each of the people in the household has any long-standing illness, health problem or disability that limits their day to day activities or the kind of work that they can do?

'By disability as opposed to ill-health, I mean a physical or mental impairment, which has a substantial and long-term adverse affect on their ability to carry out normal day-to-day activities.'

The HIH then goes through every member of the household and reports on whether that individual has a disability, a long-term illness, both or neither. For those members who are reported to have a disability or a long-term illness, the HIH is asked to indicate the nature of the illness or disability from a list of possible conditions/impairments.

A question on disability is also asked of one adult (aged 16 years and over) chosen at random from the household. This person may or may not be the same person as the highest income householder. In the 2001/2002 survey, this person was asked:

'Do you personally have any longstanding illness, health problem or disability that limits your daily activities or the work you can do? By disability as opposed to ill-health, I mean a physical or mental impairment, which has a substantial and long-term adverse affect on your ability to carry out normal day-to-day activities.'

The random adult was not asked to specify whether they considered the condition to be a disability or a long-term illness, nor were they asked to provide details of the type of condition. (Note: this question was changed from the 2003 survey to be the same as the set of questions asked of the HIH).

Comparison of the results from the HIH responses and the random adult responses show that there are some differences in how other people assess whether someone has a disability or illness and how that individual sees themselves; there are approximately 650 cases in the sample where the random adult reports no disability or long-term illness and where the HIH does report a disability or long-term illness. Table A2.1 shows the breakdown of these cases by impairment type.

These results highlight that differences in perception of whether a 'health issue' is a disability/long-term illness or not, differ by the type of condition involved. For example, differences in perception of disability/long-term illness are most common where the HIH reports that the individual has dyslexia and diabetes (18 per cent and 14 per cent respectively) whereas differences in perception are less marked in conditions relating to physical problems (arms, legs, backs).

In all of these cases, it was the response of the random adult which was considered to reflect their current disability status. All of the individuals in Table A2.1 are considered to be disabled/long-term ill by the HIH only. The actual adult does not consider themselves to have a disability/long-term illness.

There were also approximately 800 individuals who responded that they consider themselves to have a disability or long-standing illness but where the HIH responded that they did not have such. We do not have any information on the types of disability or long-term illness involved as this information was not collected during 2001/2002 on the random adult part of the survey, but we do know that they were spread equally across age groups and sex. These individuals were excluded from the disabled/long-term ill group.

Who is included in the analyses?

Two main types of analyses have been carried out: analyses at the 'person' level and analyses at 'household' level.

Individual level

Information in the tables on adults is presented for three main groups:

a) those individuals who responded that they had a disability with or without a long-term illness;
b) those individuals who only have a long-term illness;
c) those who have neither a disability or a long-term illness.

All of the results from these analyses relate to the adult (aged 16 years and over) population of Scotland.

Household level

Information on households is again presented in three main groups:

a) households where one or more person has a disability, with or without a long-term illness;
b) households where one or more person has a long-term illness only;
c) households where no members have a disability or long-term illness.

These analyses cover all of the individuals in a household, including children.

It should be noted that the SHS only covers individuals/households living at private addresses and does not cover people living in communal establishments such as care facilities, prisons, military establishments.

The Labour Force Survey

The focus and the number of questions in the health and disability module of the LFS changed in Spring 1997 to reflect the provisions of the Disability Discrimination Act (DDA) 1995. They are entirely based on self-reporting of disability and all respondents answer on their own behalf. All working age respondents are asked:

• Do you have any health problems or disabilities that you expect will last for more than a year?

If they answer 'yes' to this question, they are also asked what kind(s) of health problem or disability they have, based on a list read to them by the interviewer.

If they then answer 'yes' to the following questions:

• Does this (do these) health problem(s) or disability(ies) (when taken together or singly) substantially limit your ability to carry out normal-day-to-day activities?

OR

• They said that they had the following health problems: progressive illnesses not covered elsewhere (e.g. cancer, multiple sclerosis, symptomatic HIV, Parkinson's disease, muscular dystrophy)

Then they are defined as having a current disability covered by the DDA.

People whose health problem(s) or disability(ies) are expected to last more than a year are also asked the following questions:

• Does this health problem affect the KIND of work that you might do?
• ...or the AMOUNT of paid work that you might do?

If the respondent fulfils either of these criteria they are defined as having a work-limiting disability.

Those who meet the criteria for either (or both - as is usually the case) current DDA or work-limiting definitions of disability are defined as having a current long-term disability and are therefore included in the 'disabled' group.

The 2001 Census in Scotland

The 2001 Census in Scotland asked one question on disability/ill-health of every member of the household:

'Do you have any long-term illness, health problem or disability which limits your daily activities or the work you can do? (Include problems which are due to old age)'

Given the nature of the Census return (one per household), it is not possible to ascertain whether the response was provided by the individual themselves or whether one person completed the form on behalf of all members of the household.

One of the major advantages of using information from the Census compared to either the SHS or the LFS (other than the obvious advantage of it being a Census rather than a survey and therefore not being subject to sampling error), is that it is possible to get estimates of the entire population, including those living in communal establishments rather than just those people living within private accommodation.

Comparison of SHS, LFS and the 2001 Census

As described above, all three of these surveys rely on self definition of disability using a question along the lines of the wording used in the Disability Discrimination Act. However, the exact wording of these questions is not identical and the surveys are carried out in different ways; the SHS and LFS use computer assisted personal interviewing and have checks built into the data entry whereas the Census 2001 was a self-completion postal questionnaire. So how do the estimates from the three sources compare?

It is impossible to do a complete comparison for the whole population since the LFS only covers the working age population (16-59 years for women and 16-64 years for men). Comparison of this group for each of the three surveys shows the following:

What is the reason for the differences between the three survey estimates?

There is a variety of contributing factors to the differences in results. The major ones are likely to be differences due to the wording of the questions (although they are similar, the questions are not identical and this will have an effect on the response); differences in survey and sampling methodology; differences in timing (the Census is one day in the year whereas the other two surveys reflect results from interviews carried out over a whole year); differences in the extent to which questions are probed and followed up. In addition, there are likely to be other smaller factors which contribute to these differences. At present, we cannot quantify the impact that each of these differences has had on the results but it is an issue that the Scottish Executive will explore in future to try and gain a better understanding of how results from different sources compare and should be used alongside each other.

Which source should be used?

There is no single preferred source of information on disability in Scotland. The choice of the source will be primarily determined by the subject of interest.

The majority of the information presented in this publication is sourced from the Scottish Household Survey which was chosen for the breadth of subjects covered and for the ability to 'drill' down to get further information depending on impairment type. In order to ensure consistency, the SHS is the source which is used even when there are other sources available, unless there is a good reason for preferring another source.

Information on disability and the labour market is presented using data from the Labour Force Survey, since that is the official source of Labour Market Statistics in the UK.

Some of the demographic information presented in Chapter 1 was taken from the Census and elsewhere, other sources of information have been used to present finding on particular aspects of, or types of, disability.

Whilst the absolute size of the disabled population will differ between sources, the comparisons being made in this publication are between the disabled/ long-term ill population and the non-disabled/non long-term ill population. Thus it is possible to use information from different sources to build up a compre-hensive picture of the situation of disabled people compared to non-disabled people as long as the user is mindful of the definitions employed in each case.