Time consistency and time invariance in collective intertemporal choice (vol 176, 158, 2018)

Given a finite number of exponential discounting time preferences with at least two of them having distinct discount rates, Millner and Heal (2018) present a necessary and sufficient condition for their weighted utilitarian aggregation to be time consistent. We show by an example that the condition is sufficient but not necessary, and demonstrate that one possibility for making the condition necessary is to assume that all time preferences involved are associated with distinct discount rates. (C) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).