§ Mr. Willie W. Hamiltonasked the Paymaster General on what basis the figures for the numbers self employed are calculated; and what changes have been made in this classification since 1979.
§ Mr. Alan ClarkEstimates for the numbers of self employed are obtained from the censuses of population, the latest of which was held in 1981, updated by applying proportionate changes in self employment as estimated from the labour force survey.
The first change in methodology since 1979 was the use of labour force survey results to produce the new estimates for 1975 to 1979 which were published in January 1982 issue of Employment Gazette. The LFS data were used in place of the discontinued information from the national insurance card count.
At that time the level of staff employment was assumed by convention not to have changed since the date of the latest available survey data. When this convention was reviewed, in 1983, it was considered unrealistic. The reasons for this were set out in an article in the June 1983 edition of Employment Gazette. This article introduced a `supplementary' series which assumed that the rate of growth observed between the latest two surveys for which data were available had continued thereafter. This series was revised—and the term 'supplementary' dropped—in July 1984 using results from the 1983 LFS.
The most recent revision was published in the March 1985 edition of Employment Gazette. This revision used the 1984 LFS results, and revised results for 1983. These estimates showed an exceptional growth in self employment between 1983 and 1984 and the Department's statisticians considered it inappropriate to assume that this rate had continued. The estimates for dates after June 1984, which will be reviewed when the 1985 LFS data become available next year, incorporate the assumption that average rate of increase between 1981 and 1984 is continuing.