Why has the health inequality among infants in the US declined? Accounting for the shrinking gap
研究发现1983-2000年间美国婴儿健康差距（以阿普加评分、新生儿死亡率和婴儿死亡率衡量）在缩小，主要原因是医疗可及性提高，人口结构变化和母亲行为改变也解释了约40%的差距缩小。
Given that wealthier people are healthier, the increase in income inequality over the past two decades has led to fears that inequalities in health have also increased. Indeed, some papers have found that health disparities have become more salient among some adult populations. Using the US Vital Statistics 1983-2000, this paper presents a new stylized fact: the infant health disparity, as measured by Apgar score, neonatal mortality and infant mortality, has been narrowing over the past two decades. This is in sharp contrast to the increasing disparities in health among adults of different educational backgrounds. Using a decomposition method, I find that the most important factor in explaining the closing gap is an increase in access to medical care. All else being equal, access to proper medical care is the most important factor in explaining the narrowing infant health gap. Demographic shifts and maternal behavior changes are also significant factors, together explaining 42.2% of the closing gap in low Apgar score, 41.4% of the closing gap in neonatal death, and 45.6% of the closing gap in infant death.