As part of its Survey Programme Review, The NHS IC has commissioned NatCen to examine the extent to which results from the Health Survey for England (HSE) 2006 (carried out using face-to-face interviews) and the Boost Survey for London (carried out largely using a self-completion questionnaire) are comparable and to report on the magnitude and direction of any differences.
Despite the differences in mode, the Boost survey was designed to be as comparable with the Core survey as possible. It was intended from the outset that the two achieved samples should be combined during analyses to maximise the sample size within each Primary Care Trust (PCT) in London.
There were two main strands to the comparisons carried out in this report:
1.Response differences between the two surveys were examined in terms of the overall response levels of households and individuals, and the amount of missing data items: where respondents had refused or skipped individual questions.
2.The second strand of the analysis was to investigate the effects of measurement error attributable to the different modes of questioning.