Existing empirical studies are typically unable to sort out the direction of causality between poverty and violent crime in less developed countries. This study uses local rainfall variation – which is plausibly exogenous and closely related to income – to estimate the impact of negative income shocks on murder in 67 Tanzanian villages across eleven years. Extreme rainfall leads to a large statistically significant increase in the murder of “witches ” – typically elderly women killed by relatives – but not in other types of murders. The results are consistent with a model in which households near subsistence kill (or expel) relatively unproductive elderly household members to safeguard the nutritional status of other members. The theory is bolstered by the fact that most killings take place in low socio-economic status villages during the so-called “hungry season ” of the year, and most victims are from poor households. The results provide novel evidence on the role of poverty as a cause of violent crime.

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 or 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 (Edward A. 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 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). 1 In this short paper, 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.

There is growing interest in enhancing research transparency and reproducibility in economics and other scientific fields. We survey existing work on these topics within economics and discuss the evidence suggesting that publication bias, inability to replicate, and specification searching remain widespread in the discipline. We next discuss recent progress in this area, including through improved research design, study registration and pre-analysis plans, disclosure standards, and open sharing of data and materials, drawing on experiences in both economics and other social sciences. We discuss areas where consensus is emerging on new practices, as well as approaches that remain controversial, and speculate about the most effective ways to make economics research more credible in the future.

Most nations have experienced an internal armed conflict since 1960. Yet while civil war is central to many nations' development, it has stood at the periphery of economics research and teaching. The past decade has witnessed a long overdue explosion of research into war's causes and consequences. We summarize progress, identify weaknesses, and chart a path forward. Why war? Existing theory is provocative but incomplete, omitting advances in behavioral economics and making little progress in key areas, like why armed groups form and cohere, or how more than two armed sides compete. Empirical work finds that low per capita incomes and slow economic growth are both robustly linked to civil war. Yet there is little consensus on the most effective policies to avert conflicts or promote postwar recovery. Cross-country analysis of war will benefit from more attention to causal identification and stronger links to theory. We argue that micro-level analysis and case studies are also crucial to decipher war's causes, conduct, and consequences. We bring a growth theoretic approach to the study of conflict consequences to highlight areas for research, most of all the study of war's impact on institutions. We conclude with a plea for new and better data.

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.

Intestinal helminths—including hookworm, roundworm, whipworm, and schistosomiasis—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. We 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. Yet we do not find evidence that deworming improved academic test scores.

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 U.N. 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 (based on existing survey-based indices) accumulated significantly more unpaid parking violations. In 2002, enforcement authorities acquired the right to confiscate diplomatic plates of violators. Unpaid violations dropped sharply in response. Corruption norms and (particularly in this context) legal enforcement are both important determinants of corruption.

Using a randomized evaluation in Kenya, we measure health impacts of spring protection, an investment that improves source water quality. We also estimate households' valuation of spring protection and simulate the welfare impacts of alternatives to the current system of common property rights in water, which limits incentives for private investment. Spring infrastructure investments reduce fecal contamination by 66%, but household water quality improves less, due to recontamination. Child diarrhea falls by one quarter. Travel-cost based revealed preference estimates of households' valuations are much smaller than both stated preference valuations and health planners' valuations, and are consistent with models in which the demand for health is highly income elastic. We estimate that private property norms would generate little additional investment while imposing large static costs due to above-marginal-cost pricing, private property would function better at higher income levels or under water scarcity, and alternative institutions could yield Pareto improvements.

Despite their importance, there is limited evidence on how institutions can be strengthened. Evaluating the effects of specific reforms is complicated by the lack of exogenous variation in institutions, the difficulty of measuring institutional performance, and the temptation to “cherry pick” estimates from among the large number of indicators required to capture this multifaceted subject. We evaluate one attempt to make local institutions more democratic and egalitarian by imposing participation requirements for marginalized groups (including women) and test for learning-by-doing effects. We exploit the random assignment of a governance program in Sierra Leone, develop innovative real-world outcome measures, and use a preanalysis plan (PAP) to bind our hands against data mining. The intervention studied is a “community-driven development” program, which has become a popular strategy for foreign aid donors. We find positive short-run effects on local public goods and economic outcomes, but no evidence for sustained impacts on collective action, decision making, or the involvement of marginalized groups, suggesting that the intervention did not durably reshape local institutions. We discuss the practical trade-offs faced in implementing a PAP and show how in its absence we could have generated two divergent, equally erroneous interpretations of program impacts on institutions.