Edward Miguel

Economic Shocks and Civil Conflict: An Instrumental Variables Approach

Estimating the impact of economic conditions on the likelihood of civil conflict is difficult because of endogeneity and omitted variable bias. We use rainfall variation as an instrumental variable for economic growth in 41 African countries during 1981–99. Growth is strongly negatively related to civil conflict: a negative growth shock of five percentage points increases the likelihood of conflict by one‐half the following year. We attempt to rule out other channels through which rainfall may affect conflict. Surprisingly, the impact of growth shocks on conflict is not significantly different in richer, more democratic, or more ethnically diverse countries.

Promoting an open research culture

Author guidelines for journals could help to promote transparency, openness, and reproducibility Transparency, openness, and reproducibility are readily recognized as vital features of science (1, 2). When asked, most scientists embrace these features as disciplinary norms and values (3). Therefore, one might expect that these valued features would be routine in daily practice. Yet, a growing body of evidence suggests that this is not the case (4–6).

Quantifying the influence of climate on human conflict

Introduction Despite the existence of institutions designed to promote peace, interactions between individuals and groups sometimes lead to conflict. Understanding the causes of such conflict is a major project in the social sciences, and researchers in anthropology, economics, geography, history, political science, psychology, and sociology have long debated the extent to which climatic changes are responsible. Recent advances and interest have prompted an explosion of quantitative studies on this question. Climate and conflict across spatial scales. Evidence that temperature influences the risk of modern human conflict: (A) local violence in 1° grid cells, (B) civil war in countries, and (C) civil conflict risk in the tropics. The map depicts regions of analysis corresponding to nonparametric watercolor regressions in (A) to (C). The color intensity in (A) to (C) indicates the level of certainty in the regression line. Methods We carried out a comprehensive synthesis of the rapidly growing literature on climate and human conflict. We examined many types of human conflict, ranging from interpersonal violence and crime to intergroup violence and political instability and further to institutional breakdown and the collapse of civilizations. We focused on quantitative studies that can reliably infer causal associations between climate variables and conflict outcomes. The studies we examined are experiments or “natural experiments”; the latter exploit variations in climate over time that are plausibly independent of other variables that also affect conflict. In many cases, we obtained original data from studies that did not meet this criterion and used a common statistical method to reanalyze these data. In total, we evaluated 60 primary studies that have examined 45 different conflict data sets. We collected findings across time periods spanning 10,000 BCE to the present and across all major world regions. Results Deviations from normal precipitation and mild temperatures systematically increase the risk of conflict, often substantially. This relationship is apparent across spatial scales ranging from a single building to the globe and at temporal scales ranging from an anomalous hour to an anomalous millennium. Our meta-analysis of studies that examine populations in the post-1950 era suggests that the magnitude of climate’s influence on modern conflict is both substantial and highly statistically significant (P < 0.001). Each 1-SD change in climate toward warmer temperatures or more extreme rainfall increases the frequency of interpersonal violence by 4% and intergroup conflict by 14% (median estimates). Discussion We conclude that there is more agreement across studies regarding the influence of climate on human conflict than has been recognized previously. Given the large potential changes in precipitation and temperature regimes projected for the coming decades—with locations throughout the inhabited world expected to warm by 2 to 4 SDs by 2050—amplified rates of human conflict could represent a large and critical social impact of anthropogenic climate change in both low- and high-income countries. Climate and Conflict Knowledge silos can hinder attempts to explore questions of interest across many disciplines. Hsiang et al. (p. 1235367, published online 1 August) provide a meta-analysis of data from disciplines as disparate as archaeology and psychology to examine the relation between climate and conflict. Overall, warmer temperatures or extremes of rainfall can be causally associated with changes in interpersonal violence and in civil war. Across disciplinary boundaries, recently published evidence links climate change to increased violent conflict. A rapidly growing body of research examines whether human conflict can be affected by climatic changes. Drawing from archaeology, criminology, economics, geography, history, political science, and psychology, we assemble and analyze the 60 most rigorous quantitative studies and document, for the first time, a striking convergence of results. We find strong causal evidence linking climatic events to human conflict across a range of spatial and temporal scales and across all major regions of the world. The magnitude of climate’s influence is substantial: for each one standard deviation (1σ) change in climate toward warmer temperatures or more extreme rainfall, median estimates indicate that the frequency of interpersonal violence rises 4% and the frequency of intergroup conflict rises 14%. Because locations throughout the inhabited world are expected to warm 2σ to 4σ by 2050, amplified rates of human conflict could represent a large and critical impact of anthropogenic climate change.

Corruption, Norms, and Legal Enforcement: Evidence from Diplomatic Parking Tickets

We study cultural norms and legal enforcement in controlling corruption by analyzing the parking behavior of United Nations officials in Manhattan. Until 2002, diplomatic immunity protected UN diplomats from parking enforcement actions, so diplomats’ actions were constrained by cultural norms alone. We find a strong effect of corruption norms: diplomats from high‐corruption countries (on the basis of existing survey‐based indices) accumulated significantly more unpaid parking violations. In 2002, enforcement authorities acquired the right to confiscate diplomatic license plates of violators. Unpaid violations dropped sharply in response. Cultural norms and (particularly in this context) legal enforcement are both important determinants of corruption.

The Illusion of Sustainability

This brief summarizes the results of a gender impact evaluation study, entitled The illusion of sustainability, conducted during the time period 1998 to 2001 in Kenya. The study observed that deworming is a public good since much of its social benefit comes through reduced disease transmission. People were less likely to take deworming if their direct first-order or indirect second-order social contacts were exposed to deworming. The introduction of a small fee for deworming drugs led to an 80 percent reduction in treatment rates. Take-up was not sensitive to the exact price level, suggesting that it is particularly counter-productive to charge small positive prices for the treatment of infectious diseases. An intensive school health education had no impact on worm prevention. Funding for the study derived from World Bank, NIH Fogarty International Center, Berkeley Center for Health Research.

Global non-linear effect of temperature on economic production

Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human–natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

THE IMPACT OF CHILD HEALTH AND NUTRITION ON EDUCATION IN LESS DEVELOPED COUNTRIES

Hundreds of millions of children in less developed countries suffer from poor health and nutrition. Children in most less developed countries also complete far fewer years of schooling, and learn less per year of schooling, than do children in developed countries. Recent research has shown that poor health and nutrition among children reduces their time in school and their learning during that time. This implies that programs or policies that increase childrens health status could also improve their education outcomes. Given the importance of education for economic development, this link could be a key mechanism to improve the quality of life in less developed countries. Many researchers have attempted to estimate the impact of child health on education outcomes, but there are formidable obstacles to obtaining credible estimates. Data are often scarce, although much less scarce than in previous decades. Even more importantly, there are many possible sources of bias when attempting to estimate relationships between child health and education. This Chapter provides an overview of what has been learned thus far. Although significant progress has been made, much more research is still needed - especially in estimating the long term impact of child health status on living standards. The chapter first reviews some basic facts about child health and education in less developed countries. It then provides a framework for analyzing the impact of health and nutrition on education, describes estimation problems and potential solutions, and summarizes recent empirical evidence, including both non-experimental and experimental studies. It concludes with suggestions for future research directions.

Incentives to Learn

We study a randomized evaluation of a merit scholarship program in which Kenyan girls who scored well on academic exams had school fees paid and received a grant. Girls showed substantial exam score gains, and teacher attendance improved in program schools. There were positive externalities for girls with low pretest scores, who were unlikely to win a scholarship. We see no evidence for weakened intrinsic motivation. There were heterogeneous program effects. In one of the two districts, there were large exam gains and positive spillovers to boys. In the other, attrition complicates estimation, but we cannot reject the hypothesis of no program effect.

War and Institutions: New Evidence from Sierra Leone

Scholars of economic development have argued that war can have adverse impacts on later economic performance: war destroys physical capital and infrastructure and disrupts human capital accumulation, and it may also damage institutions by creating political instability, destroying the social fabric and endangering civil liberties (World Bank, 2003). Understanding war’s impact on development is particularly important for Sub-Saharan Africa, where two-thirds of all nations suffered from armed conflict during the 1980s and 1990s. The proliferation of armed conflict in the world’s poorest region begs the question of what role conflict may be playing in Africa’s disappointing economic performance. Yet the net long-run effects of war are ambiguous from the point of view of economic theory. To the extent that war impacts are limited to the destruction of capital, the neoclassical model predicts rapid economic growth postwar, converging back to steady-state growth. Several recent papers that study war impacts—including in Japan (Donald R. Davis and David E. Weinstein, 2002) and Vietnam (Miguel and Gerard Roland, 2005)—find few persistent local impacts of U.S. bombing, with heavily bombed areas experiencing rapid recovery to prewar population and economic trends. This is consistent with the neoclassical model if war’s main consequence is to destroy capital. War could also affect long-run growth— either positively or negatively—by modifying the scale parameter in the neoclassical growth model. For example, while the World Bank (2003) argues that war has adverse institutional consequences, Charles H. Tilly shows how war promoted state formation and nation building in Europe historically, ultimately strengthening institutions (Tilly, 1975). We study the aftermath of the recent civil conflict in Sierra Leone. One notable aspect of this project is the extensive household data for Sierra Leone on conflict experiences and on local institutions. Our results are complementary to the other recent studies mentioned above, none of which examines institutional impacts.

Promoting Transparency in Social Science Research

Social scientists should adopt higher transparency standards to improve the quality and credibility of research. There is growing appreciation for the advantages of experimentation in the social sciences. Policy-relevant claims that in the past were backed by theoretical arguments and inconclusive correlations are now being investigated using more credible methods. Changes have been particularly pronounced in development economics, where hundreds of randomized trials have been carried out over the last decade. When experimentation is difficult or impossible, researchers are using quasi-experimental designs. Governments and advocacy groups display a growing appetite for evidence-based policy-making. In 2005, Mexico established an independent government agency to rigorously evaluate social programs, and in 2012, the U.S. Office of Management and Budget advised federal agencies to present evidence from randomized program evaluations in budget requests (1, 2).