Zachary Brown

On the (Mis)Use of Wealth as a Proxy for Risk Aversion

Tests of risk sharing in the contracting literature often rely on wealth as a proxy for risk aversion. The intuition behind these tests is that since contract choice is monotonic in the coefficients of risk aversion, which are themselves assumed monotonic in wealth, the effect of a change in wealth on contract choice is clearly identified. We show that tests of risk sharing relying on wealth as a proxy for risk aversion are identified only insofar as the econometrician is willing to assume that (a) the principal is risk neutral or her preferences exhibit constant absolute risk aversion (CARA); and (b) the agent is risk neutral.

Insecticide Resistance and Malaria Vector Control: The Importance of Fitness Cost Mechanisms in Determining Economically Optimal Control Trajectories

ABSTRACT The evolutionary dynamics of insecticide resistance in harmful arthropods has economic implications, not only for the control of agricultural pests (as has been well studied), but also for the control of disease vectors, such as malaria-transmitting Anopheles mosquitoes. Previous economic work on insecticide resistance illustrates the policy relevance of knowing whether insecticide resistance mutations involve fitness costs. Using a theoretical model, this article investigates economically optimal strategies for controlling malaria-transmitting mosquitoes when there is the potential for mosquitoes to evolve resistance to insecticides. Consistent with previous literature, we find that fitness costs are a key element in the computation of economically optimal resistance management strategies. Additionally, our models indicate that different biological mechanisms underlying these fitness costs (e.g., increased adult mortality and/or decreased fecundity) can significantly alter economically optimal resistance management strategies.

A roadmap for gene drives: using institutional analysis and development to frame research needs and governance in a systems context

ABSTRACTThe deployment of gene drives is emerging as an alternative for protecting endangered species, controlling agricultural pests, and reducing vector-borne diseases. This paper reports on a workshop held in February 2016 to explore the complex intersection of political, economic, ethical, and ecological risk issues associated with gene drives. Workshop participants were encouraged to use systems thinking and mapping to describe the connections among social, policy, economic, and ecological variables as they intersect within governance systems. In this paper, we analyze the workshop transcripts and maps using the Institutional Analysis and Development (IAD) framework to categorize variables associated with gene drive governance and account for the complexities of socio-ecological systems. We discuss how the IAD framework can be used in the future to test hypotheses about how features of governance systems might lead to certain outcomes and inform the design of research programs, public engagement, and...

Stakeholder development of the Malaria Decision Analysis Support Tool (MDAST)

Background Although exceptional progress has been made towards controlling and eventually eliminating malaria from subSaharan Africa, recent efforts have sometimes faltered. Reasons for this include the development of resistance in parasites and vectors to current control strategies, volatile funding streams, and funding allocations which sometimes do not efficiently achieve the goals of project managers, policy makers, or citizens. The project described here implements an approach to evidence-based policy for malaria control using a decision analysis framework proposed by Kramer et al. [1]. The project consists of the stakeholder-driven implementation of that framework through the development of a Malaria Decision Analysis Support Tool (MDAST) in Kenya, Tanzania, and Uganda. Results from the project to date point towards large anticipated value from stakeholder-driven implementation of a tool such as MDAST at the policy, programmatic, and technical levels.

Wicked evolution: Can we address the sociobiological dilemma of pesticide resistance?

Resistance to insecticides and herbicides has cost billions of U.S. dollars in the agricultural sector and could result in millions of lives lost to insect-vectored diseases. We mostly continue to use pesticides as if resistance is a temporary issue that will be addressed by commercialization of new pesticides with novel modes of action. However, current evidence suggests that insect and weed evolution may outstrip our ability to replace outmoded chemicals and other control mechanisms. To avoid this outcome, we must address the mix of ecological, genetic, economic, and sociopolitical factors that prevent implementation of sustainable pest management practices. We offer an ambitious proposition.

Economic issues to consider for gene drives

ABSTRACTWe examine four economic issues regarding gene drive applications made possible by gene editing technologies. First, whether gene drives are self-sustaining or self-limiting will largely determine which types of organizations have incentives to develop and deploy gene drives and greatly influence their governance and regulation. Social factors will also play key roles, particularly public perceptions, with these perceptions co-determined with regulation and governance. Second, gene drive applications will generate unintended negative social impacts that will partially offset benefits. Third, economic surplus, the traditional measure of economic benefits, incompletely captures the welfare impacts of gene drive applications. Fourth, gene drives imply dynamic nonlinearities that make identifying economic equilibria and general policy recommendations challenging. The potentially substantial benefits, coupled with the technical, social, and economic uncertainties surrounding gene drives, suggest that a...

Spatial Patterns of Market Participation and Resource Extraction: Fuelwood Collection in Northern Uganda

Abstract While distance to markets is a key determinant of market participation for households that are dependent on natural resources, the distance to the resource stock is also essential. Thus, a households location with respect to markets and the resource stock determines household market participation and associated resource degradation. Applying a discrete‐choice framework for fuelwood collection in a developing country, we characterize the spatial pattern of market participation regimes and forest use. All else being equal, autarkic households are closest to the forest and furthest from the market, buyer households are closest to the market and furthest from the forest, and seller households are at intermediate distances. Empirical tests based on survey data from northern Uganda support the predictions from our theoretical model. Our findings have important implications for understanding the spatial patterns of forest degradation and determining the control group when designing impact evaluations of the effectiveness of development and conservation interventions. JEL codes: O13, Q23, Q50.

Voluntary Programs To Encourage Refuges for Pesticide Resistance Management: Lessons from a Quasi-Experiment

&NA; Economists often treat pesticide resistance as a common‐pool resource problem. While pecuniary economic incentives are the standard prescription for open‐access market failures arising from such resources, non‐pecuniary behavioral approaches (e.g., “nudges”) are also effective in some cases. Yet non‐pecuniary instruments have not previously been evaluated for managing pesticide resistance. I empirically evaluate the performance of such an intervention to manage pest resistance to genetically engineered Bacillus thuringiensis (Bt) corn. The U.S. Environmental Protection Agency permits sale of Bt seed conditional on seed producers compelling customers to plant mandated levels of non‐Bt refuge to delay the evolution of Bt resistance. Because of compliance challenges, the Bt seed producer Monsanto piloted a social marketing program to promote refuge in 17 North Carolina counties in 2013–2014. Using 2013–2016 sales data, I use difference‐in‐differences, fractional regression, discrete changes‐in‐changes, and matched differences econometric models to identify the average treatment effect of the program on refuge planting. Results suggest that if it had covered all corn growers in North Carolina, the intervention would have led the average grower to plant between 2.6% (preferred estimate) and 5.8% more refuge in 2014 compared to the counterfactual. The program increased by at least 12% the average probability of planting any refuge in 2014. I find little evidence that effects of the program persisted in subsequent years after cessation, nor that the program increased compliance with mandated refuge thresholds. Informed by behavioral economics research on other environmental and resource policies, I discuss the implications of these findings for pesticide resistance management.

An Introduction to the Proceedings of the Environmental Release of Engineered Pests: Building an International Governance Framework

In October 2016, a two-day meeting of 65 academic, government and industry professionals was held at North Carolina State University for early-stage discussions about the international governance of gene drives: potentially powerful new technologies that can be used for the control of pests, invasive species and disease vectors. Presenters at the meeting prepared seven manuscripts elaborating on the ideas raised. This BMC Proceedings issue presents the collection of these peer-reviewed manuscripts.

Liquified Petroleum Gas (LPG) Supply and Demand for Cooking in Northern Ghana

Like many other countries, Ghana relies on biomass (mainly wood and charcoal) for most of its cooking needs. A national action plan aims to expand liquefied petroleum gas (LPG) access to 50% of the country’s population by 2020. While the country’s southern urban areas have made progress toward this goal, LPG use for cooking remains low in the north. The aim of this cross-sectional study was to characterize the current state of the LPG market in this area and examine opportunities and barriers to scale up LPG adoption. We interviewed 16 LPG suppliers (stove, cylinder, and fuel vendors) as well as 592 households in the Kassena-Nankana Districts (KND) of Ghana. We find large rural–urban differences in LPG uptake: less than 10% of rural households own LPG stoves compared with over half of urban households. Awareness of LPG is high across the region, but accessibility of fuel supply is highly limited, with just one refilling station located in the KND. Affordability is perceived as the main barrier to LPG adoption, and acceptability is also limited by widespread concerns about the safety of cooking with LPG. Transitioning to a cylinder recirculation model, and providing more targeted subsidies and credit options, should be explored to expand access to cleaner cooking in this region.