NUDGE: IMPROVING DECISIONS ABOUT HEALTH, WEALTH, AND HAPPINESS by Richard H. Thaler and Cass R. Sunstein Penguin Books, 2009, 312 pp, ISBN 978-0-14-311526-7This book is best described formally as a general explanation of and advocacy for libertarian paternalism, a term coined by the authors in earlier publications. Informally, it is about how leaders, systems, organizations, and governments can nudge people to do the things the nudgers want and need done for the betterment of the nudgees, or of society. It is paternalism in the sense that "it is legitimate for choice architects to try to influence people's behavior in order to make their lives longer, healthier, and better", (p. 5) It is libertarian in that "people should be free to do what they like - and to opt out of undesirable arrangements if they want to do so", (p. 5) The built-in possibility of opting out or making a different choice preserves freedom of choice even though people's behavior has been influenced by the nature of the presentation of the information or by the structure of the decisionmaking system. I had never heard of libertarian paternalism before reading this book, and I now find it fascinating.Written for a general audience, this book contains mostly social and behavioral science theory and models, but there is considerable discussion of structure and process that has roots in mathematical and quantitative modeling. One of the main applications of this social system is economic choice in investing, selecting and purchasing products and services, systems of taxes, banking (mortgages, borrowing, savings), and retirement systems. Other quantitative social choice systems discussed include environmental effects, health care plans, gambling, and organ donations. Softer issues that are also subject to a nudge-based approach are marriage, education, eating, drinking, smoking, influence, spread of information, and politics. There is something in this book for everyone.The basis for this libertarian paternalism concept is in the social theory called "science of choice", the study of the design and implementation of influence systems on various kinds of people. The terms Econs and Humans, are used to refer to people with either considerable or little rational decision-making talent, respectively. The various libertarian paternalism concepts and systems presented are tested and compared in light of these two types of people. Two foundational issues that this book has in common with another book, Network of Echoes: Imitation, Innovation and Invisible Leaders, that was also reviewed for this issue of the Journal are that 1 ) there are two modes of thinking (or components of the brain) - an automatic (intuitive) process and a reflective (rational) process and 2) the need for conformity and the desire for imitation are powerful forces in human behavior. …

Nudge: Improving Decisions about Health, Wealth, and Happiness

The Lancet Commission on pollution and health

A common approach to evaluating robustness to omitted variable bias is to observe coefficient movements after inclusion of controls. This is informative only if selection on observables is informative about selection on unobservables. Although this link is known in theory in existing literature, very few empirical articles approach this formally. I develop an extension of the theory that connects bias explicitly to coefficient stability. I show that it is necessary to take into account coefficient and R-squared movements. I develop a formal bounding argument. I show two validation exercises and discuss application to the economics literature. Supplementary materials for this article are available online.

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Unobservable Selection and Coefficient Stability: Theory and Evidence

This brief summarizes worms: identifying impacts on education and health in the presence of treatment externalities in Kenya for the period 1998-99. Intestinal helminthes includes hookworm, roundworm, whipworm, and schistoso-miasis-infect more than one-quarter of the world's population. Studies in which medical treatment is randomized at the individual level potentially doubly underestimate the benefits of treatment, missing externality benefits to the comparison group from reduced disease transmission, and therefore also underestimating benefits for the treatment group. The author evaluate a Kenyan project in which school-based mass treatment with deworming drugs was randomly phased into schools, rather than to individuals, allowing estimation of overall program effects. The program reduced school absenteeism in treatment schools by one-quarter, and was far cheaper than alternative ways of boosting school participation. Deworming substantially improved health and school participation among untreated children in both treatment schools and neighboring schools and these externalities are large enough to justify fully subsidizing treatment.

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Worms: Identifying Impacts on Education and Health in the Presence of Treatment Externalities

Conditional cash transfers (CCTs) are programs that transfer cash, generally to poor households, on the condition that those households make pre specified investments in the human capital of their children. The report shows that there is good evidence that CCTs have improved the lives of poor people. Transfers generally have been well targeted to poor households, have raised consumption levels, and have reduced poverty, by a substantial amount in some countries. Offsetting adjustments that could have blunted the impact of transfers, such as reductions in the labor market participation of beneficiaries, have been relatively modest. The report also considers the rationale for conditioning the transfers on the use of specific health and education services by program beneficiaries. Thus CCTs have increased the likelihood that households will take their children for preventive health checkups, but that has not always led to better child nutritional status; school enrollment rates have increased substantially among program beneficiaries, but there is little evidence of improvements in learning outcomes. These findings suggest that to maximize their potential effects on the accumulation of human capital, CCTs should be combined with other programs to improve the quality of the supply of health and education services, and should provide other supporting services.

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Conditional cash transfers : reducing present and future poverty

To the extent that students benefit from high-achieving peers, tracking will help strong students and hurt weak ones. However, all students may benefit if tracking allows teachers to better tailor their instruction level. Lower-achieving pupils are particularly likely to benefit from tracking when teachers have incentives to teach to the top of the distribution. We propose a simple model nesting these effects and test its implications in a randomized tracking experiment conducted with 121 primary schools in Kenya. While the direct effect of highachieving peers is positive, tracking benefited lower-achieving pupils indirectly by allowing teachers to teach to their level. (JEL I21, J45, O15)

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Peer Effects, Teacher Incentives, and the Impact of Tracking: Evidence from a Randomized Evaluation in Kenya

Does limited access to formal savings services impede business growth in poor countries? To shed light on this question, we randomized access to noninterest-bearing bank accounts among two types of self-employed individuals in rural Kenya: market vendors (who are mostly women) and men working as bicycle taxi drivers. Despite large withdrawal fees, a substantial share of market women used the accounts, were able to save more, and increased their productive investment and private expenditures. We see no impact for bicycletaxi drivers. These results imply significant barriers to savings and investment for market women in our study context. (JEL D14, G21, J16, J23, O12, O14, O16)

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Savings Constraints and Microenterprise Development: Evidence from a Field Experiment in Kenya

Using data from a field experiment in Kenya, we document that providing individuals with simple informal savings technologies can substantially increase investment in preventative health and reduce vulnerability to health shocks. Simply providing a safe place to keep money was sufficient to increase health savings by 66 percent. Adding an earmarking feature was only helpful when funds were put toward emergencies, or for individuals that are frequently taxed by friends and relatives. Group-based savings and credit schemes had very large effects.

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Why Don't the Poor Save More? Evidence from Health Savings Experiments

Peer Effects, Teacher Incentives, and the Impact of Tracking

It is often argued that cost-sharing—charging a subsidized, positive price—for a health product is necessary to avoid wasting resources on those who will not use or do not need the product. We explore this argument through a field experiment in Kenya, in which we randomized the price at which prenatal clinics could sell long lasting anti-malarial insecticide-treated nets (ITNs) to pregnant women. We find no evidence that costsharing reduces wastage on those that will not use the product: women who received free ITNs are not less likely to use them than those who paid subsidized positive prices. We also find no evidence that costsharing induces selection of women who need the net more: those who pay higher prices appear no sicker than the average prenatal client in the area in terms of measured anemia (an important indicator of malaria). Cost-sharing does, however, considerably dampen demand. We find that uptake drops by 75 percent when the price of ITNs increases from zero to $0.75 (i.e. from 100 to 87.5 percent subsidy), the price at which ITNs are currently sold to pregnant women in Kenya. We combine our estimates in a cost-effectiveness analysis of ITN prices on child mortality that incorporates both private and social returns to ITN usage. Overall, our results suggest that free distribution of ITNs could save many more lives than cost-sharing programs have achieved so far, and, given the large positive externality associated with widespread usage of ITNs, it would likely do so at a lesser cost per life saved.

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Pascaline Dupas

Papers

Peer Effects, Teacher Incentives, and the Impact of Tracking: Evidence from a Randomized Evaluation in Kenya

Savings Constraints and Microenterprise Development: Evidence from a Field Experiment in Kenya

Why Don't the Poor Save More? Evidence from Health Savings Experiments

Peer Effects, Teacher Incentives, and the Impact of Tracking

Free Distribution or Cost-Sharing? Evidence from a Randomized Malaria Prevention Experiment