Cribsheet Summary

In Cribsheet, economist Emily Oster applies data analysis to the first years of parenting, from birth through preschool. A follow-up to her pregnancy book Expecting Better, it examines common decisions parents face—breastfeeding, sleep training, potty training, screen time, and vaccination—by weighing the actual research evidence rather than relying on conventional wisdom or parental guilt. Oster organizes much of the book around the concept of a "data-driven" approach, encouraging readers to identify the question, find the relevant studies, and consider effect sizes and study quality. She frequently distinguishes between correlation and causation, explaining why many widely cited findings (such as the link between breastfeeding and higher IQ) weaken once researchers control for confounding factors like socioeconomic status. Chapters cover topics including sleep training methods such as cry-it-out versus gentler approaches, the limited evidence that bed-sharing is dangerous under specific conditions, and the mixed findings on whether pacifier use affects breastfeeding. Oster also addresses the "mommy wars" by showing where the evidence is genuinely inconclusive, urging parents to make choices based on their own preferences and constraints. A notable recurring framework is her emphasis on cost-benefit analysis: even when a study shows a small benefit, parents must weigh it against the time, money, and stress involved. The book does not offer one-size-fits-all rules; instead, it provides tools for interpreting medical and social science research. Widely reported as a bestseller, Cribsheet aims to reduce anxiety by replacing fear-based parenting advice with statistical literacy.