§ Mr. Mitchell
To ask the Chancellor of the Exchequer how often and when the definition of unemployment used for measuring unemployment has been changed since 1979. 
§ Ms Hewitt
The information requested falls within the responsibility of the Director of the Office for National Statistics. I have asked him to reply.
Letter from Tim Holt to Mr. Austin Mitchell, dated 26 July 1999:As Director of the Office for National Statistics (ONS), I have been asked to reply to your recent parliamentary question on the definition of unemployment.The ONS measure of unemployment, derived from the Labour Force Survey (LFS), is defined on a consistent and internationally recognised basis set out by the International Labour Organisation (ILO) and counts as unemployed people who are: a) without a paid job; b) available to start work within the next two weeks and c) have either looked for work in the last four weeks or are waiting to start a job already obtained. The LFS has used the ILO definition since 1984. Prior to this a slightly different definition was used. This included people who were without a paid job who were looking for work in the reference week, or prevented from seeking work by temporary sickness or holiday, or were waiting to start a job they had already obtained or were waiting for the results of a job application. Full-time students who were seeking work but who were not available to start work in the next two weeks because they had to complete their education were excluded. The definition was used from spring 1979 to spring 1983.124WThe Labour Force Survey measure of unemployment has been compiled and published on the same definition since 1984 (annually 1984–1991; quarterly 1992 to March 1998) and a monthly moving average of each three month period from April 1998.The ONS also published the monthly numbers of people who are claiming unemployment related benefits, also known as the Claimant Count. There have been nine changes affecting the coverage of the monthly claimant count since 1979 which have been significant enough to warrant a recasting of the consistent seasonally adjusted series. Further details of these discontinuities are given in the November 1995 edition of Labour Market Trends, a copy of which is available in the House of Commons Library.