In this sixteen-minute film Paul Bradshaw and Dan Woodman discuss their experiences of working on the collection and analysis of longitudinal data in different national contexts (Scotland and Australia) and using different mixes of quantitative and qualitative methods. Through their conversation it becomes apparent that although their projects have worked with participants of different ages and their research questions are not identical, they have both gained great insights from comparisons over time. By following people in the same cohort over time and by asking the same questions of people of the same age several years apart it is possible to get a strong sense of social change (as well as continuity in relation to some issues). They also discuss how changes in technology and in policy objectives require longitudinal researchers to keep the questions that they ask under review: use of social media is far more ubiquitous to-day than it was for previous cohorts, and things that are asked about people’s use of social media have to be adjusted accordingly, while still trying to generate data that allow some comparison between cohorts. Similarly, policies relating to education and to inequality rarely stay unchanged for long, and the balance has to be struck between revising questions that have lost their relevance and keeping enough elements of a study to allow comparisons over time to be made. These time comparisons are typically over periods of years, but they do not have to be, and research projects being completed in short time periods can still employ longitudinal methods. The conversation also covered ethical challenges, researchers working as parts of teams, linkage of different data sets and secondary analysis, within the general theme that longitudinal research is a broad church within which interesting innovations are taking place all the time.

Academics in conversation: Dr Paul Bradshaw, Head of ScotCen Social Research, the Scottish arm of NatCen Social Research (webpage: http://scotcen.org.uk) and Dr Dan Woodman, University of Melbourne (webpage: https://findanexpert.unimelb.edu.au/display/person19920).