How many people are not enrolled in IDR programs but could be? Figure 1 shows that 9 percent of our sample are on IDR. The other 91 percent are not enrolled in IDR, including 69 percent of borrowers who are not eligible for IDR given their loan balance and income levels, and 22 percent of borrowers who would be eligible for IDR but are not enrolled. This suggests that for every borrower on IDR there are potentially two more who are eligible but not enrolled. 

Figure 1: For every person on IDR, there are roughly two people who could be in IDR

回想一下，如果借款人的收入相对于其初始余额(借款人所承担的原始债务金额)较低，那么借款人就有资格获得IDR. Figure 2 shows the distribution of opening balances for each of our three groups. While IDR borrowers have slightly higher opening balances, the distributions for all three groups are comparable. If original loan amounts for each group are similar, that suggests that differences in IDR eligibility must be driven by differences in income. When we look at the distribution of income within each group, we find that is the case.

Figure 2: Borrowers eligible for IDR but not enrolled have similar balances to non-eligible borrowers

Figure 3 shows the distribution of income within each of our groups. Given their similar balances, borrowers enrolled in IDR tend to have lower incomes than those not eligible for IDR. This mechanically must be true given the eligibility criteria for IDR. However, 有资格申请印尼卢比但未登记的借款人的收入甚至比目前的印尼卢比参与者低得多. Part of this is mechanical—for a fixed amount of debt, 低收入借款人更有可能符合条件，但IDR参保者的原始余额仅略高于未参保者的余额. This suggests that IDR enrollment rates are higher among high-income borrowers.

Figure 3: Borrowers eligible for IDR have significantly lower incomes

这种组合——同样大的余额，但收入低得多——提出了为什么这些借款人没有注册，为什么低收入借款人不太可能注册的问题. 一种可能性是IDR过程难以驾驭，或者相对于这些未登记借款人的预期收益而言成本过高(见, e.g., Pew 2022). 或者，这些借款人可能会对减少还款持谨慎态度，因为他们可能会为未来20年可能无法实现的承诺而在今天积累利息. 或者这些借款人可能只是想尽快还清债务，因为背负学生债务会增加其他信贷的成本, especially mortgages.

To shed light on these questions, 现在，我们将研究每个群体的借款人支付学生债务的负担程度，以及借款人管理这种负担的能力.

图4显示了以美元为单位的每一组支付金额的分布，以及借款人收入的一小部分. Equal starting balances and equal loan terms should result in equal monthly payments, 这就是我们在比较没有资格获得IDR的借款人与有资格但没有注册的借款人的月付款时所看到的(左图). 不符合条件的借款人每月还款额中位数为160美元，而符合条件但未登记的借款人每月还款额中位数为180美元. At the same time, IDR borrowers naturally have much lower payments (median of $90) because IDR mechanically lowers monthly payments. For comparison, CFPB (2019) reports an average IDR monthly payment of $97; Delisle et al. (2022) reports a range of similar estimates.

When comparing payments as a fraction of income, IDR borrowers and ineligible borrowers pay roughly the same amount (2.7% versus 3.0%), despite the lower incomes of IDR borrowers. 这可以解释为IDR平衡了低收入参保者和高收入不合格借款人的财务负担(支付占收入的百分比).

At the same time, borrowers eligible for IDR but not enrolled pay much larger portions of their take-home income. Half of them spend more than 10 percent of their take-home pay on student debt payments, and a quarter pay roughly 15 percent or more. Note that while these are very high payment burdens, they should not be surprising since IDR eligibility hinges on whether your student debt payments are more than 10 percent of your discretionary income; anyone whose payments are a small fraction of their income are ineligible for IDR.¹²

图4:有印尼卢比的借款人与没有资格获得印尼卢比的高收入借款人支付的债务数额相似

How well are eligible but not enrolled borrowers able to keep up with these large payment burdens? Figure 5 shows the fraction of borrowers in each group who made all their payments during our sample year.¹³ The fraction of borrowers keeping up with their payments is approximately equal across all three groups. Most notably, all borrowers not enrolled in IDR, eligible or not, have similar proportions keeping up with their payments (86 percent versus 82 percent), despite the much higher payment burdens among those eligible for IDR.

Figure 5: Borrowers eligible for IDR but not enrolled are keeping up with their payments despite their lower incomes

这些借款人是如何在支付了他们税后收入的10%甚至15%的情况下保持还款的呢? It is possible that these lower-income borrowers sacrifice saving or other spending  to keep up with their payments. It is also possible that they are keeping up with payments because they receive financial help from family, friends, and others, as discussed by Farrell, Greig, and Sullivan (2020). While spending behavior is beyond the scope of this report, we explore the extent of financial help received by each group in Figure 6.¹⁴

Figure 6 shows the distribution of net financial help received on student debt payments within each group.¹⁵ Median help received by eligible but not enrolled is only a few dollars a month, but the 75^th percentile of net help is just under $125 per month. This means that for a substantial fraction of these borrowers, 他们每个月的大部分付款都是由其他人支付的(回顾图4，这些借款人的月付款中位数为180美元)。. This suggests that many borrowers who are eligible for IDR are reliant on others, likely family members, to keep up with payments.¹⁶

Figure 6: Borrowers eligible for IDR but not enrolled are much more likely to receive financial help to make payments

These borrowers’ reliance on help rather than IDR may be a conscious choice: By leveraging familial resources, they can clear their debt faster which may better serve their long-term financial plans. Alternatively, family assistance could be a strategy to manage the high repayment burden: in the absence of payment relief, a borrower’s only options may be to rely on family for help or to default on the debt. IDR eligible borrowers not receiving significant help, who are the bulk of this group, face similar tradeoffs. This again raises the question of why these borrowers have not enrolled in IDR, whether they have made an affirmative decision to avoid IDR or face administrative barriers to enrollment. 我们进一步探讨了这一点，估计未登记借款人可能从IDR获得的付款减免和债务减免的金额.

While it is unclear why borrowers who are eligible for IDR do not enroll, it is likely a combination of factors. Anecdotal evidence suggests that borrowers may be overwhelmed with the complexity of IDR plans. 实验证据表明，计划选择本身是昂贵的，借款人也可能高估了他们的收入轨迹，从而低估了IDR的有用程度(考克斯), Kreisman, and Dynarski 2020). That is, many borrowers are making a conscious choice not to enroll in IDR.

In this section, we explore the financial tradeoffs IDR eligible borrowers face when choosing to enroll.

Figure 7 shows hypothetical payment relief that eligible IDR borrowers would receive if they were to enroll. The median value is shown for each quintile of take-home income within the eligible for IDR group. The median relief among the lowest earners is roughly $102 per month, or 9 percent of take-home income. Among the highest earners, monthly relief is slightly higher ($152), but this constitutes a much smaller share of their take-home income (3.5 percent).

Figure 7: Payment relief from IDR could be substantial for those who are not enrolled

This potential payment relief is substantial, especially for the lowest income borrowers, and might provide an incentive to enroll in IDR. However, 现在降低月供在未来是有代价的，因为借款人将不得不背负更长时间的债务，并可能支付更多的利息.

这种情况的一个极端情况是，当借款人的印尼盾付款低于他们每月的利息费用，债务变成负摊销, meaning their balance would grow over time. While IDR enrollees are promised forgiveness of any remaining debt after 20 years, increasing balances may still worry borrowers for several reasons. First, 关于IDR管理不善和官僚主义的报道可能会破坏借款人对他们实际上会得到宽恕的信念.¹⁷ 负摊销债务也意味着借款人将不得不在20年的信用报告中背负越来越大的债务, making other credit products like mortgages and car loans more difficult get and more expensive. In addition, if a borrower believes they will get a higher paying job in the future that would increase their IDR payment, they may have to pay back much of that accumulated interest.

Figure 8 shows how many borrowers in each income group would be negatively amortized if they were to enroll in IDR. A large majority of the lowest income borrowers would be negatively amortized, which is unsurprsing given many of them are below the cutoff for a $0 monthly payment. However, non-trivial shares of borrowers in all income groups would also be negatively amortized, including roughly a quarter of families earning more than $34,000 per year.

Figure 8: Share of potential IDR enrollees whose monthly IDR payments are less than their monthly interest charge

注册IDR的另一个潜在成本是，它将导致借款人通过延长贷款期限来支付更多的利息. 对于那些还款减免比较有限，并且将在不到20年的时间内还清贷款，因此无法获得债务减免的人来说，情况尤其如此. These borrowers will end up paying more interest on their loan compared to a standard repayment plan of 10 years.

图9显示了在IDR下，如果借款人注册并遵循其IDR付款计划，将获得减免的借款人比例. 然而，低收入借款人有望获得减免的比例很高——在收入最低的五分之一家庭中占91%，在收入第二低的家庭中占83%，实得收入超过23美元,000 are as likely to receive forgiveness as not (51 and 52 percent for the highest quintiles). This is a relatively low level of income, even for IDR enrollees; more 75 percent of current IDR enrollees in our sample make more than $23,000. Nevertheless, payment relief is not generous enough to result in forgiveness of debt for these borrowers, likely because they have a relatively small amount debt. 这也许可以解释为什么有些人不愿意使用印尼盾计价货币:许多借款人面临债务余额和收入驱动的付款金额，这使得印尼盾计价货币相对没有吸引力.

Figure 9: Half of IDR eligible borrowers with more than $23,000 in take-home income are unlikely to receive forgiveness through IDR

In summary, borrowers who are eligible for but not on IDR could receive payment relief of roughly $100 per month, freeing up more than 5 percent of their take-home income. Because their payments would be so low, 大多数借款人的贷款将负摊销，他们将获得贷款减免，只要他们保持印尼盾和良好的信誉. This should be an attractive tradeoff for many low-income borrowers, which raises the question of why they do not enroll. Possible reasons include (1) personal preference against debt—they would prefer to spend less now to pay down their debt more quickly; (2) they have other financial goals such as purchasing a home, and keeping student loan debt on their credit bureau record makes it hard or more expensive to obtain a mortgage; and (3) they would like payment relief but face administrative barriers to enrolling. 

In this section, 我们考虑了对IDR规则可能做出的一些假设变化，以及这些变化可能如何影响当前和潜在的IDR借款人. We consider three hypothetical changes to IDR which are summarized in Table 1:

1. 10-year maximum term for borrowers with small debts: This change would give borrowers with small initial debts ($10,000 or less) forgiveness after 10 years of IDR participation instead of 20.
2. Expanded Income Contingent Repayment (EICR). ¹⁸ EICR没有改变借款人必须参与多长时间才能获得减免，但它对本科生借款人每月还款的计算方式做了两项改变. First, it raises the discretionary income deduction from 150 percent of the federal poverty threshold to 200 percent. Second, instead of 10 percent of discretionary income, 借款人支付其可支配收入的5%，介于贫困线的200%至300%之间，然后支付收入超过300%的10%.
3. 5% payment burden: 我们的第三个假设遵循拜登2020年总统竞选的提议，即将学生债务偿还所需的可自由支配收入从10%降低到5%.

Table 1: Summary of possible IDR rule changes

In examining the effects of these hypothetical changes, 我们首先计算有多少借款人有资格，因为每月支付较低的印尼盾也会使更多的借款人有资格获得印尼盾.

Figure 10 shows total eligibility under each hypothetical, including those in our sample flagged as already enrolled in IDR. Under current IDR rules, 31 percent of our sample is eligible.¹⁹ Our first hypothetical, which decreases the time required to receive forgiveness, does not decrease monthly payment amounts and so does not increase eligibility relative to current IDR rules. Under our other hypotheticals, 月供下降，结果是整体资格从我们样本的31%增加到47- 48%.

Figure 10: Making IDR more generous for current enrollees can also make more borrowers eligible

In addition to increased eligibility, lower monthly payments may also decrease the total amount of money people repay over the life of their loan. Recall that lowering monthly payments also extends the amount of time a person will take to repay their loan. 任何印尼盾的借款人，如果在20年之前还清他们的余额，可能会在贷款期限内支付更多. 我们同时考虑了这两种相反的力量(更低的月供，但更长的还款期限)，通过观察贷款的总自付成本——所有本金和利息支付的总和——由借款人支付.²⁰ Specifically, 我们将每组IDR规则下的贷款总成本与遵循标准还款时间表的总成本进行比较. For example, 100%的相对成本意味着借款人支付的本金和利息与他们没有注册印尼卢比时支付的本金和利息完全相同. 请注意，我们没有区分本金和利息支付，因为许多IDR参保人获得了豁免，因此支付是否全部是利息与总自付费用的计算无关. Because we only observe one year’s worth of payments, 我们估计每个借款人在我们的样本期之前支付了多少，并假设他们将继续支付当前的印尼盾付款，直到他们的贷款还清或支付20年的印尼盾付款.²¹

图11显示了表1中描述的IDR样本中每个收入五分位数的每个IDR项目的相对成本中值. 图11中第一个有趣的项目是，在所有收入五分位数中，IDR贷款与标准10年期还款计划的相对成本中位数大致相同, hovering between 88 and 95 percent. That is, 典型的印尼卢比计划的借款人将支付大约88- 95%的金额，如果他们继续使用标准的10年期还款计划，他们将支付. However, a large portion of low-income borrowers pays relatively little under IDR and these medians mask significant variation in the distribution of total costs; see appendix Figure C. Notably, 31 percent of borrowers on IDR will pay more on IDR than they would under the standard 10-year repayment schedule. These higher costs of loan repayment under IDR are potentially somewhat surprising. First, it should be remembered that borrowers can make significant payments before enrolling in IDR. Thus, even borrowers with an IDR payment of $0 may not have a relative cost of 0 percent.

将初始债务较低的借款人的还款窗口缩短至10年，大大降低了低收入借款人的总贷款成本, but only slightly for higher income borrowers. This is likely because high-income borrowers tend to have much higher debts (Farrell, Greig, and Sullivan 2020) and so are much less likely to qualify for the decreased payoff window. For these borrowers, the terms of IDR program are unchanged.

降低月还款额(用蓝色和红色表示的假设)对低收入借款人也有类似的效果，即大幅降低贷款总成本. But under these hypothetical policies, high-income borrowers also see a substantial decrease. This is because these programs affect all borrowers, regardless of income or balance. Based on the equations underlying EICR, 收入超过联邦门槛300%的借款人每月可减少约107美元的还款, assuming a household size of one. Under the 5 percent hypothetical, all borrowers see their monthly payments cut in half. However, the restriction of these more generous changes to undergraduate debt does prevent them from being more regressive, since graduate borrowers are more likely to have higher incomes.

Figure 11: Reducing monthly payments reduces out of pocket costs for all income groups

Our results suggest that IDR may be significantly under-subscribed. A number of measures have been proposed that would likely be very effective in boosting enrollment, such as making IDR the default repayment scheme, which lab experiments show could boost enrollment significantly (Cox, Kreisman, and Dynarski 2020). This is in line with other research in behavioral economics that finds choice architecture, especially default selections like automatic 401(k) enrollment, is very influential on the choices consumers make and on their financial welfare (see., e.g., Blumenstock, Callen, Ghani 2018). But framing of the default choice can also have significant effects on consumer welfare, often in counter-intuitive ways (Bernheim, Fradkin, and Popov 2015). We find that IDR is much more beneficial for some borrowers relative to others, and this nuance may inform how enrollment boosting policies are structured.

Enrolling in IDR can immediately provide relief through lower payments and possible forgiveness in the future, but it also has costs, 直接的(额外的利息支付)和间接的(由于长期背负学生债务而增加的其他信贷成本). Among current IDR enrollees, 31% will end up paying more under IDR than under a 10-year plan and lower-income borrowers are more likely to pay more under IDR relative to the standard plan.²² Among borrowers eligible for IDR but not enrolled, we find that almost all of those with less than $16,000 in take-home income will receive some amount of forgiveness at the end of their IDR term. But only half of those with more than $23,000 will receive any forgiveness, meaning they will pay more in interest relative to a standard 10-year plan.²³ Field data also suggest that students are heavily swayed by the default choice, but many avoid IDR when IDR’s costs are brought to their attention (Abraham et al. 2020). These facts should be considered when weighing the decision of what the default payment plan should be.

A potentially lower risk strategy for increasing IDR enrollment is to reduce the paperwork burden. In a randomized experiment with actual student debtors, Mueller and Yanellis (2019) found that reducing paperwork burden could potentially double IDR enrollment.

Policymakers could also make IDR more financially attractive 通过降低特定收入水平的要求付款或减少获得宽恕所需付款的次数. This would likely induce more people to enroll in IDR, but it would also change the scenario for current IDR enrollees. Given the low IDR take-up rate under current rules, 对现有参保者的总体影响可能远大于那些被吸引新参保的借款人.

Independent of efforts to increase IDR enrollment, proposed changes to IDR itself should be thoroughly vetted. Our results suggest changes to IDR parameters—income deduction amounts, marginal payment amounts, repayment horizons—can have surprisingly large effects on who is eligible, how much current enrollees ultimately pay out of pocket, and how long borrowers carry their debt. Which parameters are changed can also affect the relative progressivity of the changes, and all of these facets should be weighed carefully.