Suchergebnisse

Abstract
Dams provide a host of benefits to societies, helping to balance variability in water availability with demand for multiple uses, allowing power generation, providing and enhancing recreation opportunities, and offering protection against damaging floods. Yet dams are often controversial due to their high investment requirements, unequal distributional effects, and concerns over the irreparable harm they may cause to free-flowing rivers and ecosystems. This paper considers the economic case for such projects, organized around a review of what we know about their value and impacts. Though heterogeneity across contexts is a common feature of interventions in many sectors, we argue that it is particularly acute in the case of dams, and that this creates difficulties for drawing general conclusions about their social value. Still, evidence suggests that investment in additional surface water storage may not always be the best solution for addressing water scarcity. Furthermore, a number of biases and blind spots exist in economic frameworks used to evaluate dams, and these often challenge analysts' ability to correctly identify which projects will be most attractive. Perhaps due to some of these perceived deficiencies, policy-makers do not appear to make much use of economic analyses for decision-making about dams. If progress is to be made in avoiding costly mistakes related to construction and removal of such infrastructures in the future, economists need to improve the realism and methods underlying their analyses of the value of dams, and offer more useful interpretations of the results that these approaches produce.

AbstractOur purpose in this paper is to review the findings of 14 randomized controlled trials (RCTs) of community-led total sanitation (CLTS) and recent rural sanitation interventions to assess their usefulness and implications for sanitation policy-making in low- and middle-income countries. The results of the RCT research programme to evaluate CLTS and related sanitation interventions suggest that the magnitude of the treatment effects was much smaller and uncertain than proponents once anticipated. For example, of the ten studies that reported results for reductions in childhood diarrhoea, only three found statistically significant decreases. Surprisingly, the RCT research teams and their funders do not seem to have thought about how their multi-million dollar research agenda would support decision-making on sanitation. Information on the parameters needed for cost-effectiveness analysis or benefit–cost analysis was not collected. However, making reasonable assumptions about the missing information on parameter values, we show that cost–benefit analysis may still 'save' CLTS because small treatment effects may still yield net positive economic benefits if the costs of implementing CLTS programmes are modest. We also discuss the need to move beyond the desire for sanitation policies that are proven to be effective globally, and the importance of focusing on analysis of the local sanitation situation. We describe the data needed to make this shift in policy focus from the global to the local level and stress the importance of interdisciplinary communication between the proponents of RCTs and 'evidence-based policy', and economists who will be responsible for the economic analysis of investments in CLTS and other sanitation interventions. We also argue that the results of these RCTs highlight the importance of coordinating investments in piped water and sanitation with investments in improved housing.

In water resources, there is a long tradition of utilization of methods to address hydrological and economic uncertainty. Less frequently considered, however, is how uncertainty rooted in political factors such as power asymmetry, the strength of institutions, and the interests of stakeholders, contributes to decision-making. This paper explores political uncertainty and its interaction with more routinely considered forms of uncertainty in international river basins. Using the example of the controversies surrounding major new infrastructure projects in the Eastern Nile Basin, we show that political uncertainty may play a key role in shaping the decisions of individual riparian countries about how to proceed with water resources development. Specifically, we consider whether uncertainty over the prospect of future cooperation might help explain why seemingly optimal economic outcomes that require cooperation (due to interconnectedness) remain elusive. We conclude with reflections on other dimensions of the water resources planning problem – climate change, changes in regional development matters, and preferences – that similarly require a framework that accounts for political uncertainty.

AbstractWe analyze the economic costs and benefits of "community-led total sanitation" (CLTS), a sanitation intervention that relies on community-level behavioral change, in a hypothetical rural region in sub-Saharan Africa with 200 villages and 100,000 people. The analysis incorporates data on the effectiveness of CLTS from recent randomized controlled trials and other evaluations. The net benefits of this intervention are estimated both with and without the inclusion of a positive health externality, that is, the additional reduction in diarrhea for an individual when a sufficient proportion of other individuals in the community construct and use latrines and thereby decrease the overall load of waterborne pathogens and fecal bacteria in the environment. We find that CLTS interventions would pass a benefit–cost test in many situations, but that outcomes are not as favorable as some previous studies suggest. The model results are sensitive to baseline conditions, including the value of time, income level used to calculate the value of a statistical life, discount rate, case fatality rate, diarrhea incidence, and time spent traveling to defecation sites. We conclude that many communities likely have economic investment opportunities that are more attractive than CLTS, and recommend careful economic analysis of CLTS in specific locations.