Discussion Paper

How Does Breastfeeding Affect IQ? Applying the Classical Model of Structured Expert Judgment

Jul 6, 2016 | Abigail Colson, Roger M. Cooke, Randall Lutter


We use the classical model, a method for structured expert judgment (SEJ), to study the effects of breastfeeding on IQ. Data on the link between breastfeeding and IQ are available, e.g., the US National Longitudinal Study of Youth, however, questions about data quality and confounding mean properly interpreting the data is not straightforward, and expert opinions diverge regarding the efficacy of breastfeeding for enhancing IQ in Western cultures. In developing countries, differing demographics and social values combined with scarcity of data render structured expert judgment an attractive method to provide policymakers with quantitative information. We find that early breastfeeding generates most of the IQ gains from full compliance with World Health Organization guidelines, and IQ gains from breastfeeding may be larger in India than the United States.