Animal welfare is often ignored in decision-making, despite widespread agreement about its importance. This is partly because of a lack of quantitative methods to assess the impacts of policies on humans and nonhumans alike on a common scale. At the same time, recent work in economics, philosophy, and animal welfare science has made progress on the fundamental theoretical challenge of estimating the well-being potential of different species on a single scale. By combining these estimates of each species’ well-being potential with assessments of how various policies impact the quality of life for these species, along with the number of animals affected, we can arrive at a framework for estimating the impact of policies on animal health and well-being. This framework allows for a quantifiable comparison between policies affecting humans and animals. For instance, it enables us to compare human QALYs to animal QALYs tailored to specific species. Hence, the intrinsic value of animal welfare impacts of policies can be monetized on the same scale as market and non-market impact for humans, facilitating benefit–cost analysis. Many challenges remain though, including issues of population ethics, political feasibility, and new complexities in addressing equity and uncertainty.

First, Mahtani argues that both in the game The Mug and in the Sleeping Beauty we should not defer to a trusted person under a particular designation if they do not self-identify under this designation. This invites a more complex Reflection Principle. I respond that there are more parsimonious ways to avoid the challenges posed to the Reflection Principle. Second, Mahtani argues that preferences create a hyperintensional context, which poses a challenge to the Ex-Ante Pareto Principle that can be averted by supervaluation. I respond that such an appeal to supervaluation would block randomization as a fair allocation device.

Much business ethics and corporate social responsibility literature suggests, implicitly or explicitly, that firms ought to engage in activities that can be characterized as philanthropy, namely, expending resources beyond what is required by law and market norms to promote others’ welfare at the expense of firm profits. However, this literature has struggled to provide a normative framework for evaluating corporate philanthropy, although scholars have noted that such expenditures can potentially remedy market failures and provide public goods more efficiently. I articulate two specific rationales that can justify corporate philanthropy based on considerations of welfare economics: 1) firms making strategic but high-risk investments in activities that are likely to generate positive externalities even if they prove unprofitable and 2) firms possessing a strong comparative advantage in their ability to address a social problem at lower social cost. Moreover, these rationales can be evaluated by a concept I develop called the philanthropy multiplier, indicating the ratio of net positive externalities to net costs. I suggest that firms consider publicizing their philanthropy multipliers, and I discuss theoretical and practical implications.

Even where willingness-to-pay as a measure of welfare impact is adjusted for diminishing marginal utility, welfare economics is shown to favour policies that add to the life expectancy or that enhance the quality of life of persons who are already better-off. I propose an alternative, Equal Respect methodology, under an axiomatic claim that at the point of decision the prospective life years of all individuals are of equal intrinsic social value. This justifies equal valuation of risk mitigation across all persons; similarly, all appraised impacts should be scaled to accord equal respect to difficult but no-less-valuable lives.

Since the publication of the seminal book Nudge by Thaler and Sunstein, several critics have highlighted preference endogeneity as a serious obstacle to nudging. When individuals hold preferences that are dynamic and endogenous to the nudge frame, it is unclear what the normative benchmark for libertarian paternalistic policies should be. While acknowledging this issue, the pro-nudging camp has not yet sufficiently addressed it. This article aims to fill this void by presenting a conditional defence of nudging when preferences are endogenous. We explain the learning process through which individuals establish ‘agentic’ preferences: preferences that are sufficiently stable, reasonable, autonomous and associated with organismic well-being to ground the ‘welfare’ principle of libertarian paternalism. To describe this process, we draw on theories from psychological science, in particular self-discrepancy theory and self-determination theory. We argue that agentic preferences are not only welfare-relevant and thus appropriate to libertarian paternalism but can also be identified by choice architects.

Most cost-benefit analyses assume that the estimates of costs and benefits are more or less accurate and unbiased. But what if, in reality, estimates are highly inaccurate and biased? Then the assumption that cost-benefit analysis is a rational way to improve resource allocation would be a fallacy. Based on the largest dataset of its kind, we test the assumption that cost and benefit estimates of public investments are accurate and unbiased. We find this is not the case with overwhelming statistical significance. We document the extent of cost overruns, benefit shortfalls, and forecasting bias in public investments. We further assess whether such inaccuracies seriously distort effective resource allocation, which is found to be the case. We explain our findings in behavioral terms and explore their policy implications. Finally, we conclude that cost-benefit analysis of public investments stands in need of reform and we outline four steps to such reform.

I comment on Sunstein's paper proposing ‘Hayekian behavioural economics’. In essence, Sunstein is merely renaming a familiar approach to normative economics, initiated in Sunstein and Thaler's seminal 2003 paper. I argue that this approach cannot fairly be described as in the spirit of Hayek's work. Sunstein's approach is based on a ‘constructivist’ conception of rationality that Hayek consistently criticized. Although both Hayek and Sunstein address ‘knowledge problems’, the two problems are fundamentally different. I develop what I claim are truly Hayekian critiques of Sunstein's claim that fuel economy mandates can be more Hayekian than carbon taxes.

Every economic explanation assumes maximization. How strange, then, that few economists accept one of maximization's most straightforward implications: every observed institution is efficient. My aim is to persuade economists of this fact and thus to dissuade them from making illogical claims about social welfare. To frame my argument, I consider the “property rights approach” to institutions developed by Yoram Barzel. I speculate that economists resist what maximization implies about institutional efficiency because they think that efficiency-always precludes them from improving the world, and hope of improving the world is what attracted them to economics in the first place. But, besides being inconsistent, resistance is unnecessary: efficiency-always does not preclude economists, or anyone else, from improving the world.

This paper discusses the challenges inherent in developing benefit-cost analysis (BCAs) of climate change. Challenges are explored from three perspectives: meeting the foundational premises for conducting BCA within the framework of welfare economics, methodological considerations that affect the application of the tools and techniques of BCA, and practical limitations that arise out of resource constraints and the nature of the question, project, or policy being evaluated. Although economic analysts frequently face – and overcome – conceptual and practical complications in developing BCAs, climate change presents difficulties beyond those posed by more conventional environmental problems. Five characteristics of the climate system and associated impacts on human and natural systems are identified that pose particular challenges to BCA of climate change, including ubiquity of impacts, intangibility, non-marginal changes, long timeframes, and uncertainty. These characteristics interact with traditional economic challenges, such as valuing non-market impact, addressing non-marginal changes, accounting for low-probability but high-impact events, and the eternal issue of appropriately discounting the future. A mapping between the characteristics of climate change and traditional economic challenges highlights the difficulties analysts are likely to encounter in conducting BCA. Despite these challenges, the paper argues that the fundamental ability of economic analysis to evaluate alternatives and tradeoffs is vital to decision making. Climate-related decisions span a wide range in terms of their scope, complexity, and depth, and for many applications of economic analyses the issues associated with climate change are tractable. In other cases it may require improved economic techniques or taking steps to ensure uncertainty is more fully addressed. Augmenting economic analysis with distribution analysis or an account of physical effects, and exploring how economic benefit and cost estimates can be incorporated into broader decision making frameworks have also been suggested. The paper concludes that there are opportunities for BCA to play a key role in informing climate change decision-making.

Hausman and McPherson defend welfare economics by claiming that even if welfare does not consist in preference satisfaction, preferences still provide good, if fallible, evidence of welfare. I argue that this strategy does not yet fully solve the problems for welfare economics stemming from the preference satisfaction theory of welfare. More work is needed to show that our self-interested preferences are sufficiently reliable, or in some other sense our best, evidence of well-being. Thus, my aim is to identify the challenges that remain and clarify what additional work is needed before Hausman and McPherson's defence of welfare economics succeeds.