scholarly journals Discounting Disentangled

2018 ◽  
Vol 10 (4) ◽  
pp. 109-134 ◽  
Author(s):  
Moritz A. Drupp ◽  
Mark C. Freeman ◽  
Ben Groom ◽  
Frikk Nesje

The economic values of investing in long-term public projects are highly sensitive to the social discount rate (SDR). We surveyed over 200 experts to disentangle disagreement on the risk-free SDR into its component parts, including pure time preference, the wealth effect, and return to capital. We show that the majority of experts do not follow the simple Ramsey Rule, a widely used theoretical discounting framework, when recommending SDRs. Despite disagreement on discounting procedures and point values, we obtain a surprising degree of consensus among experts, with more than three-quarters finding the median risk-free SDR of 2 percent acceptable. (JEL C83, D61, D82, H43, Q58)

Author(s):  
Maddalena Ferranna

The debate on the economics of climate change has focused primarily on the choice of the social discount rate, which plays a key role in determining the desirability of climate policies given the long-term impacts of climate damages. Discounted utilitarianism and the Ramsey Rule dominate the debate on discounting. The chapter examines the appropriateness of the utilitarian framework for evaluating public policies. More specifically, it focuses on the risky dimension of climate change, and on the failure of utilitarianism in expressing both concerns for the distribution of risks across the population and concerns for the occurrence of catastrophic outcomes. The chapter shows how a shift to the prioritarian paradigm is able to capture those types of concerns, and briefly sketches the main implications for the choice of the social discount rate.


2013 ◽  
Vol 4 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Mark A. Moore ◽  
Anthony E. Boardman ◽  
Aidan R. Vining

Recently, a number of authors, including Burgess and Zerbe, have recommended the use of a real social discount rate (SDR) in the range of 6–8% in benefit-cost analysis (BCA) of public projects. They derive this rate based on the social opportunity cost of capital (SOC) method. In contrast, this article argues that the correct method is to discount future impacts based on the rate of social time preference (STP). Flows in or out of private investment should be multiplied by the shadow price of capital (SPC). Using this method and employing recent United States data, we obtain an estimate of the rate of STP of 3.5% and an SPC of 2.2. We also re-estimate the SDR using the SOC method and conclude that, even if analysts continue to use this method, they should use a considerably lower rate of about 5%.


2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Arian Daneshmand ◽  
Esfandiar Jahangard ◽  
Mahnoush Abdollah-Milani

2017 ◽  
Vol 33 (3) ◽  
pp. 391-439 ◽  
Author(s):  
Hilary Greaves

Abstract:This article surveys the debate over the social discount rate. The focus is on the economics rather than the philosophy literature, but the survey emphasizes foundations in ethical theory rather than highly technical details. I begin by locating the standard approach to discounting within the overall landscape of ethical theory. The article then covers the Ramsey equation and its relationship to observed interest rates, arguments for and against a positive rate of pure time preference, the consumption elasticity of utility, and the effect of various sorts of uncertainty on the discount rate. Climate change is discussed as an application.


2017 ◽  
Vol 23 (1) ◽  
pp. 19-36 ◽  
Author(s):  
Johannes Emmerling

AbstractWe study the social discount rate, taking into account inequality within generations, that is, across countries or individuals. We show that if inequality decreases over time, the social discount rate should be lower than the one obtained by the standard Ramsey rule under certain but reasonable conditions. Applied to the global discount rate and due to the projected convergence across countries, this implies that the inequality adjusted discount rate should be about twice as high as the standard Ramsey rule predicts. For individual countries on the other hand, where inequality tends to increase over time, the effect goes in the other direction. For the United States for instance, this inequality effect leads to a reduction of the social discount rate by about 0.5 to 1 percentage points. We also present an analytical formula for the social discount rate allowing us to disentangle inequality, risk, and intertemporal fluctuation aversion.


2013 ◽  
Vol 51 (3) ◽  
pp. 894-897

Explores recent advances in the field of the social discount rate and considers how society should value the future in this context. Discusses three ways to determine the discount rate; the Ramsey rule; extending the Ramsey rule to an uncertain economic growth; random walk and mean-reversion; Markov switches and extreme events; parametric uncertainty and fat tails; the Weitzman argument; a theory of the decreasing term structure of discount rates; inequalities; discounting nonmonetary benefits; alternative decision criteria; evaluation of risky projects; the option value of uncertain projects; and evaluation of nonmarginal projects. Gollier is Professor of Economics at the University of Toulouse and Director of the Toulouse School of Economics.


2021 ◽  
pp. 230-268
Author(s):  
Joseph Heath

Recent debates have made it clear that the choice of a social discount rate has enormous consequences for the amount of carbon abatement that will be recommended. The social discount rate determines how future costs are to be compared to present costs. Philosophers have been almost unanimous in endorsing the view that the only acceptable social rate of time preference is zero, a view that, taken literally, has either absurd or extremely radical implications. The first goal of this chapter is to show that the standard arguments against temporal preference are much less persuasive than they are usually taken to be. The second goal is to explore three different avenues of argument that could be adopted in order to show that temporal discounting of welfare may be permissible. The chapter concludes with a suggestion for how deontologists could accept a pure time preference derived from the current global death rate.


2017 ◽  
Vol 14 (4) ◽  
pp. 435-462 ◽  
Author(s):  
Joseph Heath

Recent debates over climate change policy have made it clear that the choice of a social discount rate has enormous consequences for the amount of mitigation that will be recommended. The social discount rate determines how future costs are to be compared to present costs. Philosophers, however, have been almost unanimous in endorsing the view that the only acceptable social rate of time preference is zero, a view that, taken literally, has either absurd or extremely radical implications. The first goal of this paper is to show that the standard arguments against temporal preference are much less persuasive than they are usually taken to be. The second goal is to explore two different avenues of argument that could be adopted, in order to show that temporal discounting of welfare may be permissible. The first involves simply an application of the method of reflective equilibrium, while the second involves consideration of the way that our abstract moral commitments are institutionalized.


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