Two questions asked in order, one about duration and one about limitation. The routing between them is part of the definition.
A legal test, a survey question and a benefits assessment are three different instruments measuring three different things, and all three get reported as 'the number of disabled people'.
The three instruments
Each was built for a different purpose, and the population each identifies reflects that purpose. None of the three can stand in for another.
In law
The legal test
What the statutory definition actually says, and the parts of it that do the work.
The statutory test, verbatim
“a physical or mental impairment that has a substantial and long-term adverse effect on their ability to carry out normal day-to-day activities”
Equality Act 2010, section 6. In Northern Ireland the equivalent provision sits in the Disability Discrimination Act 1995. It is a threshold for protection from discrimination, drawn by Parliament and interpreted case by case — and on its own it produces no count at all.
Elsewhere on the site
The wording decides the number
Change 'long-standing illness' to 'condition expected to last 12 months' and the count moves by millions.
Who publishes what
Several bodies publish disability figures on different schedules from different instruments. Naming the source is not optional.
The employment gap
The most-quoted single figure in the field: the difference in employment rate between disabled and non-disabled people, and what it does and does not tell you.
Who is responsible for what
Statistics, regulation, enforcement and policy sit in different places, which is why no single body can answer most questions.
The six sections
Definitions
Three at once, and they do not agree.
5 entriesThe Question
The wording that decides the number.
4 entriesCounts
Who publishes what, and how often.
4 entriesGaps
The differences measured year after year.
4 entriesBodies
Who is responsible for which part.
4 entriesSources
Where a figure comes from, and how to read it.
4 entries