Doctoral Dissertation Research in Economics: Commitment Devices and Consumption Smoothing Over Illness in Western Kenya

发展中国家的贫困家庭面临着相当大的风险。尽管永久收入假说(PIH)预测家庭将完全调整消费以适应永久性收入的变化，并使消费随着临时收入的变化而平稳，但有证据表明，这两个预测都可能失败(Paxson，1992；FafChamps，Ury，and Chuukas，1998)。该项目的目标是确定可能阻止家庭平滑消费的特定因素，并评估两种旨在促进消费平滑的干预措施的有效性。该项目将专门关注家庭疾病造成的收入冲击。由于信贷在发展中国家很少，家庭可能无法平息暂时收入变化的一个明显原因是，他们缺乏安全的储蓄场所。因此，这个项目的第一个目标将是为随机选择的一部分日常收入者提供一个正式的储蓄账户。然而，即使有了正式的储蓄工具，如果家庭的消费偏好与时间不一致，他们也可能无法储蓄暂时的收入。该项目的第二个目标是为两个随机选择的治疗组提供两种承诺储蓄账户中的一种。第一组将被提供以严格执行的自我选择的每周储蓄目标为特色的目标账户，而第二组将被提供健康账户，该账户将鼓励为健康支出提款，但通过引入相对较大的非健康目的提款处罚并取消对健康提款的处罚，来阻止所有其他目的的提款。该项目将收集关于各种结果的信息，包括治疗组和对照组之间的储蓄差异，两组之间提供的劳动力的差异，以及这些账户在多大程度上用于替代其他成本更高的收入类型(例如选择投资于低收益但风险较低的资产)。然而，最重要的结果将是治疗组和对照组之间的消费对暂时性收入的不同反应。由于这项实验是在个体水平上随机进行的，标准储蓄账户的效果可以直接从标准储蓄组和对照组之间的不同反应来估计，而承诺储蓄账户的效果可以从承诺储蓄组和标准储蓄组之间的不同反应来估计。首先，它将为永久收入假说失败的具体机制提供实验证据。其次，它将为越来越多的关于承诺储蓄账户的经验相关性的文献提供补充。第三，它将测试消费对健康冲击造成的收入短暂变化的反应能力，而大多数研究侧重于降雨变化对农业收入的冲击。广泛影响这项研究的结果也可能具有有价值的政策含义。首先，提供此类账户可能代表着一种新的方法，用于设计发展中国家的储蓄账户，并为贫困家庭制定风险应对机制。其次，在某种程度上，这些账户允许家庭对疾病进行医疗治疗，从而增加他们的劳动收入，这些账户可能代表了通过改善健康来增加收入的特定机制。

Poor households in developing countries are subject to considerable risk. Although thePermanent Income Hypothesis (PIH) predicts that households will fully adjust consumption tochanges in permanent income and smooth consumption over changes in transitory income,evidence suggests that both of these predictions may fail (Paxson, 1992; Fafchamps, Udry, andCzukas, 1998).The goal of this project is to identify the specific factors that might prevent households fromsmoothing consumption over changes in transitory income and to evaluate the effectiveness oftwo interventions designed to facilitate consumption smoothing. This project will focusspecifically upon income shocks caused by household illness.As credit is rare in developing countries, one obvious reason that households may be unable tosmooth changes in transitory income is that they lack a secure place to save. The first goal of thisproject will therefore be to provide a formal savings account to a randomly selected subset ofdaily income earners.Even with formal savings vehicles, however, households may be unable to save transitory incomeif their preferences for consumption are time-inconsistent. The second goal of this project will beto provide one of two types of commitment savings accounts to two randomly selected treatmentgroups. The first group will be offered target accounts that will feature a strictly enforced selfchosenweekly savings goal while the second group will be offered health accounts that willencourage withdrawals for health expenditures but discourage withdrawals for all other purposesby introducing relatively large withdrawal penalties for non-health purposes and eliminating suchpenalties for health withdrawals.This project will collect information on a variety of outcomes, including the difference in savingsbetween the treatment and comparison groups, the difference in the labor supplied between thegroups, and the extent to which the accounts serve to substitute for other, costlier types of incomesmoothing (such as choosing to invest in lower-yielding but less risky assets). The mostimportant outcome, however, will be the differential responsiveness of consumption to transitoryincome between the treatment and comparison groups. As this experiment is randomized at theindividual level, the effect of the standard savings accounts can be estimated directly from thedifferential responsiveness between the standard savings and comparison groups and the effect ofthe commitment savings accounts can be estimated from the differential responsiveness betweenthe commitment savings and standard savings groups.Intellectual MeritThis project will be of academic interest for several reasons. First, it will provide experimentalevidence on the specific mechanisms by which the Permanent Income Hypothesis tends to fail.Second, it will add to the growing literature on the empirical relevance of commitment savingsaccounts. Third, it will test the responsiveness of consumption to transitory changes in incomedue to health shocks, in contrast to most studies which focus upon shocks to agricultural incomecaused by changes in rainfall.Broader ImpactThe results obtained from this research could potentially also have valuable policy implications.First, providing such accounts could represent a novel approach in designing savings accounts indeveloping countries and in developing risk-coping mechanisms for poor households. Second, tothe extent that the accounts allow households to medically treat illness and so increase their laborincome, the accounts could represent a specific mechanism for increasing income by improvinghealth.