We use a multi-country field experiment that combines random variation at the treatment level with exogenous variation in the length of exposure to treatment to test the effect of a slum housing intervention on the evolution of the housing aspirations of untreated co-resident neighbors. Initially after the intervention, we observe a large housing gap in favor of treated units. As a result, non-treated households’ aspirations to upgrade their housing increased sharply relative to the treatment group, echoing an aspiration to “keep up with the treated Joneses”. The aspirational effect is mostly observed among dwellers residing in urban slums, with relatively high levels of income, and located close to treated neighbors. However, after 2 years of treatment exposure, the aspirational effect completely disappears and no effects are found on housing investment. Estimates based on a structural model of aspiration adaptation show that the decay rate is 38% per month, implying that housing aspirations return to baseline levels in just 28 months. Our evidence suggests that simply fostering housing aspirations may be insufficient to encourage housing investment in poor neighborhoods, and thus slum-upgrading policies designed to indirectly stimulate housing expansion may not be as effective as they promise to be.

我们使用了一个多国野外实验，将治疗水平的随机变化与治疗暴露时间的外源性变化相结合，以测试贫民窟住房干预对未治疗的同居邻居的居住愿望演变的影响。最初，在干预之后，我们发现存在较大的住房缺口，有利于接受治疗的单位。结果，相对于治疗组，未经治疗的家庭升级住房的愿望急剧增加，呼应“继续接受治疗过的琼斯”的愿望。在居住在城市贫民窟，收入水平相对较高且靠近被治疗的邻居的居民中，通常会观察到吸气效果。但是，经过2年的治疗接触后，理想效应完全消失，对住房投资没有影响。根据吸气适应性结构模型进行的估算表明，衰减率每月为38％，这意味着住房吸气仅在28个月内就恢复到基线水平。我们的证据表明，仅仅促进住房愿望可能不足以鼓励在贫困地区的住房投资，因此旨在间接刺激住房扩张的贫民窟改造政策可能没有达到他们预期的效果。