Abstract: Improving soil carbon through conservation agriculture in developing countries may generate some private benefits to farmers, as well as sequester carbon emissions, which is a positive externality to society. Leaving crop residue on the farm has become an important option in conservation agriculture practice. However, in developing countries, using crop residue for conservation agriculture has the opportunity cost of feed for livestock. In this paper, we model and develop an expression for an optimum economic incentive that is necessary to internalize the positive externality. A crude value of the tax is calculated using data from Kenya. We also empirically investigated the determinants of the crop residue left on the farm and found that it depends on the cation exchange capacity (CEC) of the soil, the prices of maize, whether extension officers visit the plot or not, household size, the level of education of the household head, and alternative cost of soil conservation.

Abstract: This study suggests that reducing fertility should be a primary policy variable used in concert with macroeconomic policies and poverty reduction strategies. It empirically verifies the existence of a poverty demography trap by analyzing survey data from two regions in northern Tanzania. It first summarizes the macro and microeconomic issues of the relationship between GDP and population growth, highlighting poverty and demographic variables in Africa and in Tanzania. The number of children ever born (CEB) and household size in the study area indicate a high rate of population growth. Non-nuclear household members are about 23 percent, indicating heavy population pressure on household resources. The demographic variables were classified with selected poverty indicators (undernutrition and malnutrition; monetary expenditure; and access to land, clean water, sanitary facilities, and energy sources). The results showed moderate undernutrition and acute malnutrition associated with CEB and household size. Large households tend to spend much less on food, compared to smaller households. The mean weekly expenditure among households with six members is a meager US$5. As much as 50 percent of farming households do not own land and depend on wood for energy needs. Access to clean water, modern toilet facilities, and electricity is very poor, especially among large households. Getting out of the poverty trap implies reducing fertility and vice versa.

Abstract: We demonstrate the diffusion in use of Earth observations data in social science research. Our study is motivated by the continuing debate among policymakers over the value of the nation’s investment in Earth observations. We also consider the role of related factors including the spread of geographical information systems (GIS; a complementary tool for using Earth observations data) and the role of data prices. We first estimate a diffusion curve and then draw from standard bibliometric methods to evaluate further the extent to which the research field is growing. We realize that these aspects of the value of Earth observations are often part of policy debate, but we offer insights into how to substantiate and document these claims. We find evidence of increasingly widespread use of Earth observations in an ever-widening number of applications and geographic regions. GIS and data prices influence this diffusion. However, we see less evidence of a community of practice within the large social science literature represented in our data. These findings have implications for steps to take to increase the benefits of Earth observations.

Abstract: We consider a health authority seeking to allocate annual budgets optimally over time to minimize the discounted social cost of infection(s) evolving in a finite set of R >/= 2 groups. This optimization problem is challenging, since as is well known, the standard epidemiological model describing the spread of disease (SIS) contains a nonconvexity. Standard continuous-time optimal control is of little help, since a phase diagram is needed to address the nonconvexity and this diagram is 2 R dimensional (a costate and state variable for each of the R groups). Standard discrete-time dynamic programming cannot be used either, since the minimized cost function is neither concave nor convex globally. We modify the standard dynamic programming algorithm and show how familiar, elementary arguments can be used to reach conclusions about the optimal policy with any finite number of groups. We show that under certain conditions it is optimal to focus the entire annual budget on one of the R groups at a time rather than divide it among several groups, as is often done in practice; faced with two identical groups whose only di fference is their starting level of infection, it is optimal to focus on the group with fewer sick people. We also show that under certain conditions it remains optimal to focus on one group when faced with a wealth constraint instead of an annual budget.

Abstract: The nature of competition across space can be fundamentally altered by changes in market institutions. We propose a new framework that allows for the inclusion of market-altering policy changes in the spatial analysis of competitive behavior. This paper fills a gap in the literature between work that focuses on spatial price responsiveness of agents to one another and the literature that explores how policy changes in market regulations affect the competitive behavior of agents. Specifically, we account for how a change in fisheries management (the creation of catch shares) affects the spatial responsiveness of fish processors across a 21-year time period. We also introduce a method that allows for the incorporation of breaks of explanatory variables in spatial panel data sets.

Abstract: An understanding of the uncertainty in benefit and cost estimates is a critical part of a benefit–cost analysis. Without a quantitative treatment of uncertainty, it is difficult to know how much confidence to place in these estimates. In 2002, an NRC report recommended that EPA move toward conducting probabilistic, multiple-source uncertainty analyses in its RIAs with the specification of probability distributions for major sources of uncertainty in the benefit estimates. In 2006, reports by GAO and RFF found that EPA had begun to address the NRC recommendations, but that much remained to be done to meet the NRC concerns. This paper provides a further review of EPA’s progress in developing a quantitative assessment of the uncertainties in its health benefits analyses for the RIAs for four recent NAAQS rulemakings. In conclusion, EPA’s recent RIAs present the results of its uncertainty analyses in piecemeal fashion rather than providing an overall, comprehensive statement of the uncertainty in its estimates. In addition, its recent RIAs continue to focus on the concentration-response relationship and largely fail to address the uncertainty associated with the other key elements of the benefits analysis.

Abstract: We looked at risk and ambiguity attitudes among Ethiopian peasants in one of the poorest regions of the world and compared their attitudes to a standard Western university student sample elicited by the same decision task. Strong risk aversion and ambiguity aversion were found with the Ethiopian peasants, and these attitudes are similar to those of the university students. Testing for the effect of socioeconomic variables on uncertainty attitudes showed that poor health increased both risk and ambiguity aversion.

Abstract: We investigated attitudes toward positionality among rural farmers in northern Ethiopia, using a tailored two-part survey experiment. On average, we found positional concerns neither in income per se, nor in income from aid projects among the farmers. These results support the claim that positional concerns are correlated with absolute level of income of a country.

Abstract: Using a natural field experiment in a recreational site, a public good almost fully dependent on voluntary donations, we explored the crowding-out effect of gift rewards. First, we investigated whether receiving a map in appreciation of a donation crowded out prosocial behavior and found no significant effect of giving the map. Second, we explored the effect of adding the map to a treatment designed to increase donations. Interestingly, when the gift was combined with our attempt to trigger reputational and self image motives, the probability of donating decreased significantly, compared to the social reference treatment alone.

Abstract: This paper presents an institutional analysis of the underlying factors affecting the performance of drinking-water community organizations in rural areas of Costa Rica. These organizations provide water to more than 60 percent of the total rural population. There is, however, a great disparity in their performance. This research tries to understand how a complex configuration of geophysical characteristics of watersheds and infrastructure as well as governance and socioeconomic attributes of local users affects three key dimensions of performance in rural communities: financial health, infrastructure condition, and user satisfaction. Using a qualitative approach and matching techniques to ensure comparability, the paper analyzes four communities in depth. The main results highlight the relevance of a demand-driven approach, coupled with local accountability, working rules for tariff collection and infrastructure maintenance, and appropriate support from the government as the main conditions that promote higher levels of performance.

Abstract: Despite the global environmental benefits of increasing the amount of protected areas, how these conservation policies affect the well-being of nearby individuals is still under debate. Using household surveys with highly disaggregated geographic references, we explored how national parks affect local wages in Costa Rica and how these effects vary within different areas of a park and among different social groups. We found that a park’s effects on wages vary according to economic activity and proximity to the entrance of the park. Wages close to parks are higher only for people living near tourist entrances. Workers close to entrances are not only employed in higher-paid activities (nonagricultural activities) but also receive higher wages for these activities. Agricultural workers, however, are never better off close to parks (neither close to or far from the entrances). Also, workers close to parks but far away from tourist entrances earn similar or lower wages than comparable workers far away from parks. Our results are robust to different econometric approaches (OLS and matching techniques). The location of national park entrances and the possibility that agricultural workers can switch to higher-paid service activities near tourist entrances may be important tools for helping local workers take advantage of the economic benefits of protected areas.

Abstract: World oil supply disruptions lead to U.S. economic losses. Because oil is fungible in an integrated world oil market, increased oil consumption, whether from domestic or imported sources, increases the economic losses associated with oil supply disruptions. Nevertheless, increased U.S. oil production expands stable supplies and dampens oil price shocks, whereas increased U.S. oil imports boosts the share of world oil supply that comes from unstable producers and exacerbates oil price shocks. Some of the economic losses associated with oil supply disruptions—gross domestic product losses and some transfers abroad—are externalities that can be quantified as oil security premiums. To estimate such premiums for domestic and imported oil, we take into account projected world oil market conditions, probable oil supply disruptions, the market response to oil supply disruptions, and the resulting U.S. economic losses. Our estimates quantify the security externalities associated with increased oil use, which derive from the expected U.S. economic losses resulting from potential disruptions in world oil supply.

Abstract: Most developed and developing country governments levy taxes on gasoline and diesel fuel used by motor vehicles. However, outside of the United States and Europe, automobile and heavy truck externalities have not been quantified, so policymakers have little guidance on whether prevailing tax rates are anywhere close to their corrective levels. This paper develops a general approach for roughly gauging the magnitude of motor vehicle externalities, and hence the corrective tax on gasoline and diesel, for individual countries, based on pooling local data sources with extrapolations from U.S. data. The analysis is illustrated for the case of Chile, though it could be readily applied to other countries with appropriate data collection.