How Long is a Piece of Elastic? The Measurement of Female Activity Rates in British Censuses, 1951-1981

The labour force is conventionally defined as all those employed, or seeking work - whether or not registered as unemployed. In Britain, this total of economically active persons has only been observed intermittently in Censuses and Surveys. Data for the regular Working Population refers to the employed plus registered unemployed only. The principal source for the post war period is the decennial Census of Population (1951-81). We show in this paper that the inference of a comparable time series of female economic activity rates from these data is not at all straightforward as the way in which economic activity was recorded altered on each occasion. We document these changes in reliability and likely direction of errors in Census evidence. Finally we adjust the Census information in the light of our activity rates by age group "less inconsistent" with the definition of economic activity as adopted by the EEC Labour Survey which is the most regular source likely to be available in the future. Since the 1971 Census seems to have been exceptionally extensive in its coverage of the economically active, the revised series makes the longer run upward trend seem to have been smoother than the crude data suggest.