世界経済・社会統計 = World development indicators

Offering a unifying theoretical perspective not readily available in any other text, this innovative guide to econometrics uses simple geometrical arguments to develop students' intuitive understanding of basic and advanced topics, emphasizing throughout the practical applications of modern theory and nonlinear techniques of estimation. One theme of the text is the use of artificial regressions for estimation, reference, and specification testing of nonlinear models, including diagnostic tests for parameter constancy, serial correlation, heteroscedasticity, and other types of mis-specification. Explaining how estimates can be obtained and tests can be carried out, the authors go beyond a mere algebraic description to one that can be easily translated into the commands of a standard econometric software package. Covering an unprecedented range of problems with a consistent emphasis on those that arise in applied work, this accessible and coherent guide to the most vital topics in econometrics today is indispensable for advanced students of econometrics and students of statistics interested in regression and related topics. It will also suit practising econometricians who want to update their skills. Flexibly designed to accommodate a variety of course levels, it offers both complete coverage of the basic material and separate chapters on areas of specialized interest.

Estimation and Inference in Econometrics

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

We investigate conditions sufficient for identification of average treatment effects using instrumental variables. First we show that the existence of valid instruments is not sufficient to identify any meaningful average treatment effect. We then establish that the combination of an instrument and a condition on the relation between the instrument and the participation status is sufficient for identification of a local average treatment effect for those who can be induced to change their participation status by changing the value of the instrument. Finally we derive the probability limit of the standard IV estimator under these conditions. It is seen to be a weighted average of local average treatment effects.

Evolution and Rationality Some Recent Game-Theoretic Results. Identification and Estimation of Local Average Treatment Effects

This project will deliver help to reduce the vulnerability of poor people in Haiti to the effects of climate change, while at the same time conserving threatened coastal and marine biodiversity. Investments in climateproofed and socially-sustainable BD conservation strategies, within the context of the National Protected Areas System (NPAS), will enable coastal and marine ecosystems to continue to generate Ecosystem-Based Adaptation (EBA) services; while additional investment of adaptation funds in the watersheds which drain into these ecosystems will serve to maximize BD benefits and ecosystem functions, as well as generating EBA benefits for the populations living in the watersheds themselves.

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The United Nations Development Programme

Poor rural and urban households in developing countries face substantial risks, which they handle with risk-management and risk-coping strategies, including self-insurance through savings and informal insurance mechanisms. Despite these mechanisms, however, vulnerability to poverty linked to risk remains high. This article reviews the literature on poor households use of risk-management and risk-coping strategies. It identifies the constraints on their effectiveness and discusses policy options. It shows that risk and lumpiness limit the opportunities to use assets as insurance, that entry constraints limit the usefulness of income diversification, and that informal risk-sharing provides only limited protection, leaving some of the poor exposed to very severe negative shocks. Public safety nets are likely to be beneficial, but their impact is sometimes limited, and they may have negative externalities on households that are not covered. Collecting more information on households vulnerability to poverty through both quantitative and qualitative methods can help inform policy.

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Income Risk, Coping Strategies, and Safety Nets

The influence of the environment and environmental change is largely unrepresented in standard theories of migration, whilst recent debates on climate change and migration focus almost entirely on displacement and perceive migration to be a problem. Drawing on an increasing evidence base that has assessed elements of the influence of the environment on migration, this paper presents a new framework for understanding the effect of environmental change on migration. The framework identifies five families of drivers which affect migration decisions: economic, political, social, demographic and environmental drivers. The environment drives migration through mechanisms characterised as the availability and reliability of ecosystem services and exposure to hazard. Individual migration decisions and flows are affected by these drivers operating in combination, and the effect of the environment is therefore highly dependent on economic, political, social and demographic context. Environmental change has the potential to affect directly the hazardousness of place. Environmental change also affects migration indirectly, in particular through economic drivers, by changing livelihoods for example, and political drivers, through affecting conflicts over resources, for example. The proposed framework, applicable to both international and internal migration, emphasises the role of human agency in migration decisions, in particular the linked role of family and household characteristics on the one hand, and barriers and facilitators to movement on the other in translating drivers into actions. The framework can be used to guide new research, assist with the evaluation of policy options, and provide a context for the development of scenarios representing a range of plausible migration futures.

The effect of environmental change on human migration

Much has been written on the determinants of input and technology adoption in agriculture, with issues such as input availability, knowledge and education, risk preferences, profitability, and credit constraints receiving much attention This paper focuses on a factor that has been less well documented: the differential ability of households to take on risky production technologies for fear of the welfare consequences if shocks result in poor harvests Building on an explicit model, this is explored in panel data for Ethiopia Historical rainfall distributions are used to identify the counterfactual consumption risk Controlling for unobserved household and time-varying village characteristics, it emerges that not just exante credit constraints, but also the possibly low consumption outcomes when harvests fail, discourage the application of fertiliser The lack of insurance causes inefficiency in production choices

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Consumption Risk, Technology Adoption and Poverty Traps: Evidence From Ethiopia

Most studies examining the dynamics of welfare have found large fluctuations in consumption over relatively short periods, suggesting substantial short‐run movements in and out of poverty. The consequence is that cross‐section poverty research may not be able to identify the poor. In this study, we explore this short‐run variability further. We use a data set on a panel of 1450 households in different communities in rural Ethiopia, surveyed thrice, over 18 months. On average year‐to‐year poverty is very similar. However, we find high variability in consumption and poverty, over the seasons and year‐by‐year. Econometric analysis suggests that consumption is affected by idiosyncratic and common shocks, including rainfall and household‐specific crop failure, while households respond to seasonal incentives related to changing labour demand and prices. The results imply that a larger number of households are vulnerable to shocks than implied by the standard poverty statistics, while some of the non‐poor in the...

Vulnerability, seasonality and poverty in Ethiopia

Using panel data from villages in rural Ethiopia, the paper studies the determinants of consumption growth (1989-97), based on a microgrowth model, controlling for heterogeneity. Consumption grew substantially, but with diverse experiences across villages and individuals. A key focus is on whether shocks affect growth. Rainfall shocks have a substantial impact on consumption growth, and its impact presists for many years. There also appears to be a significant, persistent growth impact from the largescale famine in the 1980s, as well as substantial externalities from the presence of road infrastructure. The findings related to the persistent effects of rainfall shocks and the famine crisis imply that welfare losses due to the lack of insurance and protection measures are well beyond the welfare cost of short term consumption fluctuations.

Stefan Dercon

Papers

Income Risk, Coping Strategies, and Safety Nets

The effect of environmental change on human migration

Consumption Risk, Technology Adoption and Poverty Traps: Evidence From Ethiopia

Vulnerability, seasonality and poverty in Ethiopia

Growth and Shocks: evidence from rural Ethiopia