31 March 2004 - DWP in-house report 128: review of disability estimates and definitions
Research published today by the Department for Work and Pensions and conducted by the National Centre for Social Research examines the range and methodological validity of survey estimates of the prevalence of disability in Britain and the definitions of disability used in government social surveys. The study examines the relative merits and methodological robustness of a variety of estimates of the prevalence of disability produced by surveys.
The main findings are as follows:
- There can be no single, ‘gold standard’ estimate of the prevalence of disability – a variety of estimates are required for different purposes in and outside government.
- Estimates of the prevalence of disability for specific age groups (up to State Pension Age) do not differ markedly between surveys. However, estimates of the prevalence of disability are significantly less stable for people above state pension age than those below state pension age.
- Much of the variation between estimates arises from the use of different definitions of disability (what is being measured) and the age range of the populations to which they apply - eg all adults or those of working age only (who is being measured). Variation is also caused by how disability is measured; for example, differently worded questions or the order in which questions are asked may have an effect on the estimate produced.
- In addition to the issues that can affect the accuracy of survey-based estimates of all phenomena, several specific issues complicate the measurement of disability. These include – accessibility issues for people with certain impairments (for example, someone with a visual impairment may find it difficult to complete a self-completion questionnaire); difficulties with measuring issues relating to experiences of people with fluctuating conditions; the lack of a single, accepted definition of what ‘disability’ means.
- Estimates produced using the definition of disability uses in the DDA appeared to vary the most out of the three definitions commonly used in surveys. The report states that this is mainly because the definition is relatively new and is the least standardised in terms of how the question is asked in surveys.
Notes for editors
- The Department for Work and Pensions is also issuing a Ministerial Press release, which outlines the Department’s response to the findings of this review.
- The review involved a technical review of existing surveys and estimates of the prevalence of disability in the population, a consultation exercise with key stakeholders and users of disability estimates and an exploration of possible next steps to help ensure consistent use of the most robust and relevant estimates.
- Review of disability estimates and definitions by Madhavi Bajekal, Tim Harries, Rachel Breman, and Kandy Woodfield, DWP In-House Report series (no. 128) and User’s guide to disability estimates and definitions, Mike Tibble are published on 31st March 2004. A summary and copy of the report and user’s guide are available on the DWP website: http://www.dwp.gov.uk/asd/asd5/index.html
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