We study an at-scale natural experiment in which debit cards were given to cash transfer recipients who already had a bank account. Using administrative account data and household surveys, we find that beneficiaries accumulated a savings stock equal to 2% of annual income after two years with the card. The increase in formal savings represents an increase in overall savings, financed by a reduction in current consumption. There are two mechanisms. First, debit cards reduce transaction costs of accessing money. Second, they reduce monitoring costs, which led beneficiaries to check their account balances frequently and build trust in the bank.

中文翻译：

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借记卡如何让穷人节省更多

我们研究了一个大规模的自然实验，其中向已经拥有银行账户的现金转账收款人提供借记卡。使用行政账户数据和住户调查，我们发现受益人在持卡两年后积累了相当于年收入 2% 的储蓄存量。正式储蓄的增加代表了总体储蓄的增加，其资金来源是当前消费的减少。有两种机制。首先，借记卡降低了取钱的交易成本。其次，他们降低了监控成本，这导致受益人经常检查他们的账户余额并建立对银行的信任。