- What is the BHPS sample size and how was it selected?
- Have any new samples been added since the start of the survey?
- How do I know which sample a respondent belongs to?
The original BHPS sample was 5,050 households containing 9,092 interviewed adults at wave 1 (1991) with a response rate of 74% of eligible households. The sample was a stratified clustered design with 250 Primary Sampling Units in England, Scotland and Wales and was designed to be representative of the GB population (excluding Northern Ireland and North of the Caledonian Canal). The BHPS BHPS Quality Profile contains information about the sample; see also the Sample Details section of the data documentation.
Since the BHPS is a household panel study with a longitudinal design, all members of a sampled household are interviewed. Each household member’s sample status can vary depending on whether they are an original sample member or not. The variable wSAMPST indicates the individual’s status with respect to their sample – e.g. whether they are an original sample member, a new permanent sample member, or a temporary sample member. Researchers should decide how to treat each sample member according to the purposes of their own research. The BHPS Quality Profile contains information about the following rules; the Longitudinal Following Rules section of the data documentation also details these definitions.
The BHPS data are made up of five samples:
- Original BHPS from 1991 to present. This is the main BHPS sample (n=5,050 households)
- Former European Community Household Panel survey low-income sub-sample from1997 to 2001 (Waves 7 to 11) (n=1,000 households)
- Welsh extension from 1999 (Wave 9) (n=1500 households)
- Scottish extension from 1999 (Wave 9) (n=1500 households)
- Northern Ireland extension from 2001 (Wave 11) (n=1900 households)
The variable wMEMORIG on the individual level data records indicates the sample membership for each individual. The variable wHHORIG indicates the sample membership for each household on the household level data records. The record xWLSTEN also includes the variable MEMORIG which indicates the most recent sample status for all individuals ever enumerated in the panel.