Inconsistency in intertemporal choice : a behavioral approach

Purpose: The purpose of this paper is to introduce the main measures of inconsistency in the context of intertemporal choice and to identify the relationships between them (more specifically, the measures by Prelec, Takahashi and Rohde). In effect, Thaler (1981), awarded the Nobel Prize in Economics 2017, argued that when a preference must be expressed between two reward options, some people may reverse their original preference when a significant delay is introduced before the reward is to be received. This anomaly is known as inconsistency in intertemporal choice. Design/methodology/approach: After a revision of the existing literature and by using the methods from mathematical calculus, the authors have derived the logical relationships between the measures presented in this paper. Findings: The main contribution of this paper is the proposal of a novel parameter, the so-defined ratio of two instantaneous discount rates, which the authors call the instantaneous variation rate, which allows relating some other measures of inconsistency, namely the measures described by Prelec and Rohde. A limitation of this paper is the unavailability of empirical information about the inconsistency measures needed to substantiate the theoretical findings. Indeed, this paper has social implications because recent behavioral and neuroeconomic studies have shown the existence of preference reversal or time inconsistency in other areas. The authors' models can be implemented in these fields in order to better analyze the situations of inconsistency. Originality/value: The originality of this paper lies in the authors' aim to bring some order to the proposed measures of inconsistency which have arisen as a result of the different approaches adopted.