Abstract：
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 to 2010, we employ a difference-in-differences estimator for C-sections, low Apgar, and low birth weight measures. We find that the reversal of a multi-site, high profile, randomized control trial on the appropriate delivery of term breech births, the Term Breech Trial, led to a 15%-23% decline in C-sections for such births at a time when the overall trend in C-sections was rising. We find our largest estimated effects amongst traditionally disadvantaged groups (i.e., non-white, and minimal education). However, we do not find that such a change in practice had significant impacts on infant health. Contrary to prior studies, we find that physicians updated their beliefs quickly, and do indeed adjust to new medical research, particularly young physicians, prior to mandatory policy or professional guidelines.
摘要：
当一项著名医学研究的发现被推翻时，会发生什么？使用一项关于臀位出生的医学试验，我们估计了这种医学研究的逆转对医师选择和婴儿健康结局的影响.使用1995年至2010年的美国出生证明记录，我们对剖腹产采用差异估计法，低阿普加，和低出生体重措施。我们发现多站点的逆转，高调,足月臀位分娩的随机对照试验，学期臀位试验，在剖腹产的整体趋势上升的时候，导致此类分娩的剖腹产下降了15%-23%。我们在传统弱势群体中发现了我们最大的估计影响(即，非白色,和最低限度的教育)。然而,我们没有发现这种实践变化对婴儿健康有重大影响。与以前的研究相反，我们发现医生很快更新了他们的信念，确实适应了新的医学研究，特别是年轻的医生，在强制性政策或专业指南之前。
