We use data from the Population Assessment of Tobacco Use and Health (PATH), a longitudinal data set including self-reported and biomarker measures of tobacco use, to examine the effects of state-level tobacco 21 (T21) laws on smoking and vaping. T21 laws reduce self-reported cigarette smoking...

What happens when the findings of a prominent medical study are overturned? Using a medical trial on breech births, we estimate the effect of the reversal of such a medical study on physician choices and infant health outcomes. Using the United States Birth Certificate Records from 1995-2010, we...