What Research Questions Should the Next Generation of Birth Cohort Studies Address? An International Delphi Study of Experts

Objective: Birth cohort studies (BCS) have generated a wealth of invaluable basic scientific and policy-relevant information on a wide range of issues in child health and development. This study sought to explore what research questions are currently a priority for the next generation of BCS using a 3-round Delphi survey of interdisciplinary experts. Methods: Twenty-four (Round I, N = 17; Round II, N = 21; Round III, N = 18) experts across a wide range of fields (eg, psychology, public health, and maternal/child health) agreed to participate. In Round I, the expert panel was invited to freely respond to the question, “what are the key scientific questions future birth cohort studies should address?” Content analysis of answers was used to identify 47 questions for rating on perceived importance by the panel in Round II and consensus-achieving questions were identified. Questions that did not reach consensus in Round II were posed again for expert re-rating in Round III. Results: Twenty six of 47 questions reached consensus in Round II, with an additional 6 reaching consensus in Round III. Consensus-achieving questions rated highly on importance spanned a number of topics, including environmental effects on child development, intergenerational transmission of disadvantage, and designing BCS to inform intervention strategies. Conclusion: Investigating the effects of family/environmental factors and social disadvantage on a child's development should be prioritized in designing future BCS. The panel also recommended that future BCS are designed to inform intervention strategies.