Unemployment is a count of jobless people who want to work, are available to work, and are actively seeking employment. The ILO definition is used internationally, so comparisons between countries can be made, and it also allows for consistent comparisons over time. Unemployment is calculated using data from the Labour Force Survey (LFS), so it is subject to sampling differences.

The claimant count measures only those people who are claiming unemployment-related benefits (Jobseeker's Allowance). It is always the lower measure because some unemployed people are not entitled to claim benefits, or choose not to do so. Benefits rules vary over time and between different countries, so it is more difficult to make comparisons. The claimant count comes from the administrative records of Jobcentre Plus (formerly Employment Service), and is available earlier than the LFS-based unemployment data.

When employment is high the gap between unemployment and the claimant count tends to widen, as some jobless people who were not previously looking for work start to do so. By actively looking for work they may become classified as unemployed under the ILO definition. However they do not feature in the claimant count unless they also begin to claim benefits.

The difference between the two measures is wider for women than for men. Currently fewer than half of unemployed women claim unemployment-related benefits compared with around three quarters of men.