On the Measurement of Poverty Dynamics

This paper introduces a family of multi-period poverty measures derived from commonly used static poverty measures. Our measures trade-off poverty levels and changes (gains and losses) over time, and are consistent with loss aversion. We characterize the partial ranking over income dynamics induced by these measures and use it in two empirical applications with longitudinal household level data. Comparing two decades of income dynamics in the United States we find that the income dynamics of the 1990s -post Welfare reform- dominates the income dynamics of the 1980s -pre Welfare reform. Next, we compare the contemporary income dynamics of three industrialized countries and conclude that United Kingdom dominates Germany and United States, and Germany dominates the United States if poverty stocks are given more importance than poverty flows. The differences between our ranking and those obtained using other welfare criteria such as social mobility suggest that our measures capture critical information about the evolution of poverty.

On the Measurement of Poverty Dynamics

This paper introduces a family of multi-period poverty measures derived from commonly used static poverty measures. Our measures trade-off poverty levels and changes (gains and losses) over time, and are consistent with loss aversion. We characterize the partial ranking over income dynamics induced by these measures and use it in two empirical applications with longitudinal household level data. Comparing two decades of income dynamics in the United States, we find that the income dynamics of the 1990s-post Welfare reform dominates the income dynamics of the 1980s-pre Welfare reform. Next, we compare the contemporary income dynamics of three industrialized countries and conclude that United Kingdom dominates Germany and United States, and Germany dominates the United States if poverty stocks are given more importance than poverty flows. The differences between our ranking and those obtained using other welfare criteria such as social mobility suggest that our measures capture critical in formation about the evolution of poverty

Saving More to Borrow Less: Experimental Evidence from Access to Formal Savings Accounts in Chile

Poverty is often characterized not only by low and unstable income, but also by heavy debt burdens. We find that the inability to save contributes to this indebtedness. Access to free savings accounts substantially decreases participants' propensity to use short-term credit. In addition, participants who experience an economic shock have less need to reduce consumption, and subjective well-being improves significantly. Precautionary savings and credit therefore act as substitutes in providing self-insurance, and participants prefer saving more when given the choice. Take-up patterns suggest that requests by others for participants to share their resources are a key obstacle to saving

Under-Savers Anonymous: Evidence on Self-Help Groups and Peer Pressure as a Savings Commitment Device

While commitment devices such as defaults and direct deposits from wages have been found to be highly effective to increase savings, they are unavailable to the millions of people worldwide who not have a formal wage bill. Self-help peer groups are an alternative commitment device that is widespread and highly accessible, but there is little empirical evidence evaluating their effectiveness. We conduct two randomized field experiments among low-income micro-entrepreneurs in Chile. The first experiment finds that self-help peer groups are very potent at increasing savings. In contrast, a more classical measure, a substantially increased interest rate, has no effect on the vast majority of participants. A second experiment is designed to unbundle the key elements of peer groups as a commitment device, through the use of regular text messages. It finds that surprisingly, actual meetings and peer pressure do not seem to be crucial in making self-help peer groups an effective tool to encourage savings

Under-Savers Anonymous: Evidence on Self-Help Groups and Peer Pressure as a Savings Commitment Device

We test the effectiveness of self-help peer groups as a commitment device for precautionary savings, through two randomized field experiments among 2,687 Chilean micro-entrepreneurs. The first experiment finds that self-help peer groups are a powerful tool to increase savings (the number of deposits grows 3.7-fold and the average savings balance almost doubles). In contrast, a more classical measure, a substantially increased interest rate, has no effect for most participants. A second experiment tests an alternative delivery mechanism and shows that effects of similar size can be achieved by holding people accountable through feedback text messages, without meetings or peer pressure

Impact evaluation methods in public economics : a brief introduction to randomized evaluations and comparison with other methods

Recent years have seen a large expansion in the use of rigorous impact evaluation techniques. Increasingly, public administrations are collaborating with academic economists and other quantitative social scientists to apply such rigorous methods to the study of public finance. These developments allow for more reliable measurements of the effects of different policy options on the behavioral responses of citizens, firm owners, or public officials. They can help decision makers in tax administrations, public procurement offices, and other public agencies design programs informed by well-founded evidence. This article provides an introductory overview of the most frequently used impact evaluation methods. It is aimed at facilitating communication and collaboration between practitioners and academics by introducing key vocabulary and concepts used in rigorous impact evaluation methods, starting with randomized controlled trials and comparing them with other methods ranging from simple pre–post analysis to difference-in-differences, matching estimations, and regression discontinuity designs

Mesenchymal Transition and PDGFRA Amplification/Mutation Are Key Distinct Oncogenic Events in Pediatric Diffuse Intrinsic Pontine Gliomas

Diffuse intrinsic pontine glioma (DIPG) is one of the most frequent malignant pediatric brain tumor and its prognosis is universaly fatal. No significant improvement has been made in last thirty years over the standard treatment with radiotherapy. To address the paucity of understanding of DIPGs, we have carried out integrated molecular profiling of a large series of samples obtained with stereotactic biopsy at diagnosis. While chromosomal imbalances did not distinguish DIPG and supratentorial tumors on CGHarrays, gene expression profiling revealed clear differences between them, with brainstem gliomas resembling midline/thalamic tumours, indicating a closely-related origin. Two distinct subgroups of DIPG were identified. The first subgroup displayed mesenchymal and pro-angiogenic characteristics, with stem cell markers enrichment consistent with the possibility to grow tumor stem cells from these biopsies. The other subgroup displayed oligodendroglial features, and appeared largely driven by PDGFRA, in particular through amplification and/or novel missense mutations in the extracellular domain. Patients in this later group had a significantly worse outcome with an hazard ratio for early deaths, ie before 10 months, 8 fold greater that the ones in the other subgroup (p = 0.041, Cox regression model). The worse outcome of patients with the oligodendroglial type of tumors was confirmed on a series of 55 paraffin-embedded biopsy samples at diagnosis (median OS of 7.73 versus 12.37 months, p = 0.045, log-rank test). Two distinct transcriptional subclasses of DIPG with specific genomic alterations can be defined at diagnosis by oligodendroglial differentiation or mesenchymal transition, respectively. Classifying these tumors by signal transduction pathway activation and by mutation in pathway member genes may be particularily valuable for the development of targeted therapies

Savings accounts to borrow less: experimental evidence from Chile

Poverty is often characterized not only by low and unstable income, but also by heavy debt burdens. In a randomized field experiment with over 3,500 low-income micro-entrepreneurs in Chile, we find that providing access to free savings accounts decreases participants’ shortterm debt. In addition, participants who experience an economic shock have less need to reduce consumption, and subjective well-being improves significantly. Precautionary savings and credit therefore act as substitutes in providing self-insurance, and participants prefer borrowing less when a free formal savings account is available. Take-up patterns suggest that requests by others for participants to share their resources may be a key obstacle to saving