Choosing the future: Markets, ethics and rapprochement in social discounting
Antony Millner (University of California, Santa Barbara and National Bureau of Economic Research) and Geoffrey Heal (Columbia University and National Bureau of Economic Research)
GPI Working Paper No. 13-2021, published in Journal of Economics Literature
This paper provides a critical review of the literature on choosing social discount rates (SDRs) for public cost-benefit analysis. We discuss two dominant approaches, the first based on market prices, and the second based on intertemporal ethics. While both methods have attractive features, neither is immune to criticism. The market-based approach is not entirely persuasive even if markets are perfect, and faces further headwinds once the implications of market imperfections are recognised. By contrast, the ‘ethical’ approach – which relates SDRs to marginal rates of substitution implicit in a single planner’s intertemporal welfare function – does not rely exclusively on markets, but raises difficult questions about what that welfare function should be. There is considerable disagreement on this matter, which translates into enormous variation in the evaluation of long-run payoffs. We discuss the origins of these disagreements, and suggest that they are difficult to resolve unequivocally. This leads us to propose a third approach that recognises the immutable nature of some normative disagreements, and proposes methods for aggregating diverse theories of intertemporal social welfare. We illustrate the application of these methods to social discounting, and suggest that they may help us to move beyond long-standing debates that have bedevilled this field.
Other working papers
Time discounting, consistency and special obligations: a defence of Robust Temporalism – Harry R. Lloyd (Yale University)
This paper defends the claim that mere temporal proximity always and without exception strengthens certain moral duties, including the duty to save – call this view Robust Temporalism. Although almost all other moral philosophers dismiss Robust Temporalism out of hand, I argue that it is prima facie intuitively plausible, and that it is analogous to a view about special obligations that many philosophers already accept…
Prediction: The long and the short of it – Antony Millner (University of California, Santa Barbara) and Daniel Heyen (ETH Zurich)
Commentators often lament forecasters’ inability to provide precise predictions of the long-run behaviour of complex economic and physical systems. Yet their concerns often conflate the presence of substantial long-run uncertainty with the need for long-run predictability; short-run predictions can partially substitute for long-run predictions if decision-makers can adjust their activities over time. …
Crying wolf: Warning about societal risks can be reputationally risky – Lucius Caviola (Global Priorities Institute, University of Oxford) et al.
Society relies on expert warnings about large-scale risks like pandemics and natural disasters. Across ten studies (N = 5,342), we demonstrate people’s reluctance to warn about unlikely but large-scale risks because they are concerned about being blamed for being wrong. In particular, warners anticipate that if the risk doesn’t occur, they will be perceived as overly alarmist and responsible for wasting societal resources. This phenomenon appears in the context of natural, technological, and financial risks…