David M. Frank

Chagas Disease Risk in Texas

Background Chagas disease, caused by Trypanosoma cruzi, remains a serious public health concern in many areas of Latin America, including México. It is also endemic in Texas with an autochthonous canine cycle, abundant vectors (Triatoma species) in many counties, and established domestic and peridomestic cycles which make competent reservoirs available throughout the state. Yet, Chagas disease is not reportable in Texas, blood donor screening is not mandatory, and the serological profiles of human and canine populations remain unknown. The purpose of this analysis was to provide a formal risk assessment, including risk maps, which recommends the removal of these lacunae. Methods and Findings The spatial relative risk of the establishment of autochthonous Chagas disease cycles in Texas was assessed using a five–stage analysis. 1. Ecological risk for Chagas disease was established at a fine spatial resolution using a maximum entropy algorithm that takes as input occurrence points of vectors and environmental layers. The analysis was restricted to triatomine vector species for which new data were generated through field collection and through collation of post–1960 museum records in both México and the United States with sufficiently low georeferenced error to be admissible given the spatial resolution of the analysis (1 arc–minute). The new data extended the distribution of vector species to 10 new Texas counties. The models predicted that Triatoma gerstaeckeri has a large region of contiguous suitable habitat in the southern United States and México, T. lecticularia has a diffuse suitable habitat distribution along both coasts of the same region, and T. sanguisuga has a disjoint suitable habitat distribution along the coasts of the United States. The ecological risk is highest in south Texas. 2. Incidence–based relative risk was computed at the county level using the Bayesian Besag–York–Mollié model and post–1960 T. cruzi incidence data. This risk is concentrated in south Texas. 3. The ecological and incidence–based risks were analyzed together in a multi–criteria dominance analysis of all counties and those counties in which there were as yet no reports of parasite incidence. Both analyses picked out counties in south Texas as those at highest risk. 4. As an alternative to the multi–criteria analysis, the ecological and incidence–based risks were compounded in a multiplicative composite risk model. Counties in south Texas emerged as those with the highest risk. 5. Risk as the relative expected exposure rate was computed using a multiplicative model for the composite risk and a scaled population county map for Texas. Counties with highest risk were those in south Texas and a few counties with high human populations in north, east, and central Texas showing that, though Chagas disease risk is concentrated in south Texas, it is not restricted to it. Conclusions For all of Texas, Chagas disease should be designated as reportable, as it is in Arizona and Massachusetts. At least for south Texas, lower than N, blood donor screening should be mandatory, and the serological profiles of human and canine populations should be established. It is also recommended that a joint initiative be undertaken by the United States and México to combat Chagas disease in the trans–border region. The methodology developed for this analysis can be easily exported to other geographical and disease contexts in which risk assessment is of potential value.

Group Decisions in Biodiversity Conservation: Implications from Game Theory

Background Decision analysis and game theory [1], [2] have proved useful tools in various biodiversity conservation planning and modeling contexts [3]–[5]. This paper shows how game theory may be used to inform group decisions in biodiversity conservation scenarios by modeling conflicts between stakeholders to identify Pareto–inefficient Nash equilibria. These are cases in which each agent pursuing individual self–interest leads to a worse outcome for all, relative to other feasible outcomes. Three case studies from biodiversity conservation contexts showing this feature are modeled to demonstrate how game–theoretical representation can inform group decision-making. Methodology and Principal Findings The mathematical theory of games is used to model three biodiversity conservation scenarios with Pareto–inefficient Nash equilibria: (i) a two–agent case involving wild dogs in South Africa; (ii) a three–agent raptor and grouse conservation scenario from the United Kingdom; and (iii) an n–agent fish and coral conservation scenario from the Philippines. In each case there is reason to believe that traditional mechanism–design solutions that appeal to material incentives may be inadequate, and the game–theoretical analysis recommends a resumption of further deliberation between agents and the initiation of trust—and confidence—building measures. Conclusions and Significance Game theory can and should be used as a normative tool in biodiversity conservation contexts: identifying scenarios with Pareto–inefficient Nash equilibria enables constructive action in order to achieve (closer to) optimal conservation outcomes, whether by policy solutions based on mechanism design or otherwise. However, there is mounting evidence [6] that formal mechanism–design solutions may backfire in certain cases. Such scenarios demand a return to group deliberation and the creation of reciprocal relationships of trust.

Ethics of the scientist qua policy advisor: inductive risk, uncertainty, and catastrophe in climate economics

This paper discusses ethical issues surrounding Integrated Assessment Models (IAMs) of the economic effects of climate change, and how climate economists acting as policy advisors ought to represent the uncertain possibility of catastrophe. Some climate economists, especially Martin Weitzman, have argued for a precautionary approach where avoiding catastrophe should structure climate economists’ welfare analysis. This paper details ethical arguments that justify this approach, showing how Weitzman’s “fat tail” probabilities of climate catastrophe pose ethical problems for widely used IAMs. The main claim is that economists who ignore or downplay catastrophic risks in their representations of uncertainty likely fall afoul of ethical constraints on scientists acting as policy advisors. Such scientists have duties to honestly articulate uncertainties and manage (some) inductive risks, or the risks of being wrong in different ways.

On Joseph Spengler’s “Have Values a Place in Economics?”*

In the 1934 article “Have Values a Place in Economics?,” the American population economist Joseph Spengler discussed the ethical responsibilities of economic experts and the relationship between economic science and human values. Spengler decided to examine these topics in part due to “the current economic depression” ð313Þ, and his paper is worth revisiting in light of the recent financial crisis, particularly due to the complicity of professional economists in producing it. I first discuss Spengler’s view on the obligations of economic experts, then connect Spengler’s view of values in economics to contemporary debates in philosophy of social science. I suggest that Spengler did not go far enough in identifying the moral obligations of economic experts, or in specifying roles for values and ethical considerations within economic methodology itself. In his characterization of economics as a science, Spengler maintained a strong fact-value distinction. Like natural scientists, economists are primarily concerned with establishing relationships between variables and formulating and testing explanatory hypotheses. But economics is also analogous to medicine in that its results are directly relevant to human well-being. Spengler’s argument for the obligation of economic experts to contribute to normative discussion of issues like economic inequality, poverty, and taxation relies on this analogy: “1⁄2for economists to remain silent on social issues is comparable to competent cancer specialists remaining silent in the face of the claims of quacks” ð331Þ. By virtue of their expertise, economists incur an obligation to honestly communicate their results to society, lest “charlatans and selfish individuals” ð316Þ formulate economic policy. While Spengler was clear that this argument only goes so far as economic expertise will take it, he also limited his de-

Conservation Goals and Species Preservation: Uncertainty and Multiple Values

The author argues that species preservation should be deemphasized as an ecosystem management goal, due to its infeasibility in the context of rapid ecological change under plausible scenarios of global climate change. I argue that for neither reservation-based nor relocation-based strategies do the author’s arguments necessarily hold. Decisions about locating conservation areas and potentially managing population relocations will be made under significant uncertainty and in the presence of multiple values. The paper discusses the uncertainty associated with species distribution models and the question of whether conserving biodiversity in general and maintaining ecosystem services may, in some cases, depend strongly on species preservation goals. In the case of managed relocation, the author focuses on values that are destroyed by human intervention. However, I argue that these are not the only values at stake in these decisions, and that values of biocultural affiliation with particular species may play an important role in managed relocations.