Parent-Child Quality Time: Does Birth Order Matter?
利用美国时间使用调查数据，发现头胎孩子每天比二胎孩子多获得20-30分钟的亲子优质时间，这源于父母随时间分配时间的方式，为出生顺序影响儿童发展提供了解释。
Using data from the American Time Use Survey, I find that a first-born child receives 20-30 more minutes of quality time each day with his or her parent than a second-born child of the same age from a similar family. The birth-order difference results from parents giving roughly equal time to each child at any point in time while the amount of parent-child quality time decreases as children get older. These results provide a plausible explanation for recent research showing a very significant effect of birth order on child outcomes.