Quarterly Journal of Economics · 2025 · [{"name": "Tim de Silva", "affiliation": ["Stanford University"]}]
中文摘要
摘要 采用收入或有偿还(income-contingent repayment)的学生贷款为借款人提供了应对收入风险的保险, 但可能削弱其赚取更高收入的激励。利用澳大利亚收入或有偿还安排的一次变动, 我发现借款人会减少劳动供给以降低其还款额。这些反应在工时灵活性更高、还款概率更低以及流动性约束更紧的借款人中更为显著。我利用这些反应估计了一个带摩擦的动态劳动供给模型, 这些摩擦导致调整不完全。我的估计表明, 劳动供给对收入或有偿还的反应限制了政府提供的学生贷款中的最优保险规模。然而, 这些反应过小, 不足以证明固定还款合同的合理性: 在保持税收与转移支付体系不变的情况下, 将现有学生贷款从固定还款重组为受约束最优(constrained-optimal)的收入或有贷款, 可在不增加额外财政成本的前提下提升借款人福利, 其幅度相当于终身消费增加0.8%。
Abstract
Abstract Student loans with income-contingent repayment insure borrowers against income risk but can reduce their incentives to earn more. Using a change in Australia’s income-contingent repayment schedule, I show that borrowers reduce their labor supply to lower their repayments. These responses are larger among borrowers with more hourly flexibility, a lower probability of repayment, and tighter liquidity constraints. I use these responses to estimate a dynamic model of labor supply with frictions that generate imperfect adjustment. My estimates imply that the labor supply responses to income-contingent repayment limit the optimal amount of insurance in government-provided student loans. However, these responses are too small to justify fixed-repayment contracts: restructuring existing student loans from fixed repayment to a constrained-optimal income-contingent loan—while keeping the tax and transfer system unchanged—increases borrower welfare by the equivalent of a 0.8% increase in lifetime consumption at no additional fiscal cost.