Borrowing Trouble? Human Capital Investment with Opt-In Costs and Implications for the Effectiveness of Grant Aid
利用联邦佩尔助学金公式的回归断点设计，发现每增加1美元助学金，借款学生贷款减少1.80美元，这种挤出效应仅出现在需要学生主动选择贷款的学校，且可能因减少学生流动资金而降低学业成就。
We estimate the effect of grant aid on City University of New York (CUNY) students' borrowing and attainment using a regression discontinuity/kink design based on the federal Pell Grant formula. Each dollar of grant aid reduces loans by $1.80 among borrowers. We only find crowd-out of this magnitude in colleges that, like CUNY, “offer” no loan aid and require students to opt into borrowing. We develop and empirically support a model that shows opt-in or other fixed borrowing costs can lead grants to crowd out large amounts of loan aid, lowering some students' attainment by reducing their liquid resources.