• By Dartington SRU
  • Posted on Wednesday 05th January, 2011

Holding a mirror to policy makers

In many ways, says Michael Wadsworth, “birth cohort studies are driven by policy challenges before the subsequent insights may be utilized for policy change.” Wadsworth is in perhaps a unique position to know; he was the director of the first of these large studies in the UK, which began tracing babies born in one week of 1946. To make his point, he cites the example of the 1946 and 1958 British birth cohort studies. These were came about largely as a result of the desire to understand better the causes of high infant mortality and falling fertility, and the consequences of school selection processes and their impact on subsequent access to training and further education. But it was, and remains, an expensive and brave decision for policy makers to fund large-scale longitudinal studies - particularly seeing that the learning from such studies will typically take years, or even decades, to crystallize. During this time, of course, governments come and go. Decisions to mount such studies are thus rarely driven by party political motives, but a shared and enduring commitment to learn more about the processes of human development and how society influences the course of individual’s lives. But once the decision to fund a large-scale birth cohort study has been taken - as has occurred in five out of the last seven decades - the subsequent findings can, in turn, be powerful drivers for policy change. Birth cohort studies influence policy in three main ways, believes Wadsworth. “First,” he argues, “there is an increased awareness – and, critically, an understanding of the consequences - of problems, so that change can come about.” For example, the early British cohort studies demonstrated the detrimental effects of poor visitation rights for parents and the lack of emotional support for sick children in hospital. This informed the influential Platt report in 1959. The study also highlighted the meagre extent of pain relief for the high proportion of mothers who gave birth at home: just 20 per cent of such women received pain relief compared to more than 50 per cent of those giving birth in hospitals.“Second”, says Wadsworth, “birth cohort studies allow us to chart the socio-economic and geographical distribution of problems, and, by following individuals over many years, understand the individual and societal burden imposed.” This allows policy makers to recognise the consequence of inequalities in society, such as disparities in healthcare and education provision, and respond accordingly. Third, birth cohort studies allow policy-makers to understand the impact of policy change on the lives of individuals and groups. Perhaps the clearest example, according to Wadsworth, is how consecutive birth cohort studies undertaken since the 1940s have charted the reduction in health inequalities attributable to the development of the National Health Service. Yet while birth cohort studies allow the positive impact of policy change to be documented, they also play another role, according to John Bynner, the director of the 1958 and 1970 studies: “They hold a mirror to policy-makers reflecting the failures to reduce some inequalities over decades, such as the persistent disparity between the educational and economic opportunities of varying socio-economic groups.” Finally, longitudinal studies have been, and will continue to remain, critical to the design of evidenced-based programs and interventions. Data from these studies about how individual, family, neighborhood and societal risks affect children’s subsequent development form the basis upon which interventions to reduce such risks are built. For example, Wadsworth notes that British birth cohort studies were instrumental in establishing how beneficial home visits by health visitors are in the early years of children’s physical development. These insights have informed the design and structure of evidence-based programs such as the Nurse Family Partnership. So what lies in the future for Britain’s birth cohort studies and what potential do they have to both increase our understanding of human development and influence policy? According to Bynner, aside from the advances coming decades will see in relation to our understanding of how genes and physiology interact with the environment to influence development (referred to as GxE), perhaps the most salient benefit of birth cohort studies will be their role in predicting the costs and benefits of particular courses of policy or practice intervention. Data from longitudinal studies form the foundation upon which estimations about the economic costs of not intervening are made, which, in turn, are used to estimate the potential savings that may be made by particular courses of intervention. This, he argues, is particularly important for policy-makers in the current economic climate where greater confidence is required that limited resources are spent in the most efficient and beneficial way. In addition, Wadsworth believes that as the birth cohorts mature their value to science and policy increases. The early cohorts are now approaching older age, so their data will prove invaluable in informing health and social care strategies as policy-makers seek to support the burgeoning ageing population.This is why, both Wadsworth and Bynner argue, we must continue to follow both existing cohorts well into adulthood, and also why we must continue to establish new birth cohorts - such as the one proposed to begin in 2012-13 - so that we may understand how development is influenced by the changing social, demographic and economic world we live in, and by the policies implemented that affect us all.

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