本文嘗試於補習已成社會風氣且勞動工資為外生固定參數的前提下，討論 當社會存在父母所得有高有低、而小孩資質雖不同但分配相同的兩個所得階層 家庭時，政府擴增大學名額和降低高等教育學費，對會支援補習的家長（或補 習學生）總人數、補習總支出和跨代向上流動的影響。我們認為大學名額的擴 增將同時提升高所得和低所得家庭小孩受高等教育的比例，利於向上跨代流 動；並因聯考最低錄取分數的降低，鼓勵原本無望錄取的考生，選擇加入補 習，復以人口結構中高等教育畢業之技術勞力家庭比例增加，願意讓小孩補習 的家長數目增多，而使得社會之補習總人數和補習總支出皆上升。其次，當政 府對高等教育採低學費政策時，將因降低教育成本而增強受高等教育誘因，低 所得和高所得家庭的補習支出均上揚；若高等教育名額不變且補習支出對聯考 分數的提升具邊際報酬遞減作用時，低學費政策並將利於向上跨代流動。

This study sets up to develop a cramming-for-examination model with an economy characterized by heterogeneous-ability individuals, an educational quota for attending universities, and capital market imperfection, in an attempt to discuss the possible impacts of educational quotas and low-tuition policies on cramming decisions and social mobility. We show that an increase in educational quotas might increase the cramming expenditures and social mobility since they raise the opportunities for median-ability individuals to pass the entrance examination by cramming for examinations. However the low-tuition policy will be good for social upward mobility only in a specific condition.