The Rug Rat Race
研究发现美国高学历父母在1990年代中期后大幅增加育儿时间，而低学历父母增加较少，这不能用收入效应解释，而可能与大学入学竞争加剧有关。
After three decades of decline, the amount of time spent by parents on childcare in the United States began to rise dramatically in the mid-1990s. This increase was particularly pronounced among college-educated parents. Less educated mothers increased their childcare time by over 4 hours per week, and college-educated mothers increased theirs by over 9 hours per week. Fathers showed the same patterns, but with smaller magnitudes. Why would highly educated parents increase the time they allocate to childcare at the same time that their returns from paid employment have skyrocketed? Finding no empirical support for standard explanations, such as selection or income effects, we argue instead that increased competition for college admissions may be an important factor. We provide empirical support for our explanation with a comparison of trends between the United States and Canada, across ethnic groups in the United States, and across U.S. states.