Some brief reflections following the MRC Population Cohort Strategy Workshop, London 6th March 2013.
The MRC organised a very interesting meeting in London on Wednesday 6th March, focusing on developing a future strategy for population cohorts. In preparation for the meeting, the MRC had conducted a review of cohorts and had gathered information on a total of 31 separate studies. These range from large scale national studies such as the Million Women Study to rather smaller studies such as DASH (Determinants of Adolescent Social well-being and Health), a study of a multiethnic adolescent cohort in London that investigates social and biological influences on ethnic differences in health and wellbeing.
Many people at the meeting commented on the extraordinary richness, number, and diversity of longitudinal datasets available for health-related research in Britain. Indeed several people said that an accessible web-based directory of all the current longitudinal studies would be very welcome. Information about international longitudinal studies would also be very helpful (and the comment was made that any British strategy should be aware of the international context).
What is surprising perhaps is that there are already directories of cohort studies in existence but many people are not aware of these resources. I’ve listed a few of the ones I’ve come across below.
‘Our Changing Lives’ website
This website was created a few years ago to showcase some of the main British longitudinal datasets and also has a list with links to sixteen international studies. This resource was jointly funded by ESRC, MRC and The Wellcome Trust. One issue is how such resources are advertised but also how they stay up-to-date.
This was another initiative designed to allow researchers to search for appropriate data resources. It has details on over 500 separate studies (although it is no longer funded and seems not to have been updated since 2004).
While this one’s still in development, it promises to offer an easier way of browsing summaries of individual studies. There are currently details of 33 separate studies, many of which are longitudinal.
At the UK Data Service there is a very helpful summary of nine major longitudinal studies, including the 1958 cohort study, Understanding Society and the English Longitudinal Study of Aging. The UK Data Service also provides researchers with access to datasets from the studies.
Going beyond Britain, www.birthcohorts.net provides an international inventory of birth cohort studies, while the IALSA research network provides links to studies focusing on aging. In addition, the RAND Survey metadata repository provides study level information, but also includes a searchable library of survey questions, a search engine for finding comparable questions across the surveys, and a set of identically defined variables for cross-country analysis.
There was also a light-hearted debate at the end of the day about which was the first ever cohort study. Albert Hoffman suggested it was Wilhelm Weinberg’s 1913 Large Retrospective Cohort Study of the children of tuberculosis patients’ children, George Davey Smith contested that an even earlier example of a cohort study is the work in the 1860s in Scotland by Arthur Mitchell on the surveillance and care of the insane.
Regardless of which was the first-ever cohort study, we know that Britain has an unparalleled portfolio of longitudinal studies. The challenge is to ensure that the research community knows about these rich and valuable data resources.
…if you know of any other good directories of cohort studies please leave a comment here and I’ll add them to the list.