The design and content of the HALCyon qualitative study: A qualitative sub-study of the National Study of Health and Development and the Hertfordshire Cohort Study.

This paper provides an overview of the design of a qualitative sub-study of 30 members of the 1946 British birth cohort study, known as the Medical Research Council (MRC) National Survey of Health and Development (NSHD), and 30 members of the older Hertfordshire Cohort Study (HCS) who were born between 1931 and 1939. Interviews were carried out in 2010 as part of the Healthy Ageing across the Life Course (HALCyon) collaborative research programme1 . The central objective of this part of the research programme was to use qualitative in-depth biographical interviews to help understand how an individual’s self-reported physical capability impacts on their health, wellbeing and social interaction. In this descriptive methodological paper, we focus on the content of the interview topic guide, our sampling strategy and on the characteristics of the sample that was achieved in comparison with the overall survey population. Descriptive summary statistics and brief examples of responses to key questions are included.