Educational Attainment and Cohort Size
论证美国战后婴儿潮导致过去三十年教育经济回报和教育成就大幅波动，高学历者因年轻与老年工人替代性随教育程度降低而收入受损，从而降低教育激励，而婴儿潮前后队列则相反。
"We argue that the postwar baby boom [in the United States] caused substantial fluctuations in both the economic rewards to education and educational attainment over the last 3 decades. If substitutability between young and old workers diminishes with education, the present value of lifetime earnings for a boom cohort is depressed more for highly educated workers, reducing incentives for educational attainment. The opposite is true for pre- and postboom cohorts. The diminishing substitutability hypothesis explains the declines in both the returns to college and college completion rates in the 1970s and predicts a substantial increase in educational attainment for postboomers."