Sampling methodology and fieldwork changes in the October Household Surveys and Labour Force Surveys

Abstract

The 1999 October Household Survey was the first time that Statistics South Africa introduced a master sample of Enumeration Areas. There were several important changes in sampling and fieldworker practice that accompanied the introduction of the master sample of Enumeration Areas, which have not been systematically documented and which make comparability of the surveys undertaken by Statistics South Africa before and after this time difficult. We document these changes in this research note and provide evidence that these changes were partly responsible for the odd trends in the total number of single-person households estimated from the October Household Surveys and the Labour Force Surveys, as well as rapid increases in employment, in the late 1990s.

Keywords:

• sampling methods
• employment
• demography
• household surveys
• South Africa

Acknowledgements

The authors thank Cally Ardington from Southern Africa Labour and Development Research Unit for her suggestion to explore the number of households per EA in different surveys, which helped lead to some of the findings reported in this paper, and Peter Buwembo from Stats SA for explaining the multiple household dwelling point sampling methods and for sourcing the OHS 1996 fieldworker manual.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

³Hodge (2009) comments that the introduction of the master sample may have affected the estimates of total employment in the October Household Surveys, but did not investigate this any further. Buwembo (2010) explains how multi-household dwelling points were sampled differently before the introduction of the master sample but does not document the other changes we describe here.

⁴The Quarterly Labour Force Surveys replaced the LFSs in 2008. As far as we are aware there were no major sampling changes between the LFS and the Quarterly Labour Force Surveys, so we concentrate on the OHSs and LFSs in this article.

⁵Stats SA (2005:xxiv) defines a dwelling unit as ‘any structure or part of a structure or group of structures occupied by one or more than one household; or which is vacant or under construction but could be lived in at the time of the survey. The dwelling unit is the major listing unit for this survey'. In the early OHSs, dwelling units were called visiting points.

⁶According to the OHS questionnaires these data were collected in every wave of the OHSs before 1999. Unfortunately this was not made available in the public release data for OHS 1997 and OHS 1998.

⁷The increase was even larger if the end point was any of the first three LFSs, but these were outliers affected by massive measured subsistence agricultural employment (in the first two LFSs) that was never repeated in any subsequent LFS (and was not related to the changes in sampling and fieldwork we discuss here, which occurred in OHS 1999 and not with the introduction of the LFSs) and massive informal self-employment (in the third LFS) as a result of monetary incentives paid to enumerators to conduct the follow-up Survey of Employers and Self-employed. Thus, we compare OHS 1997 and LFS September 2001.