Delay discounting rates are temporally stable in an equivalent present value procedure using theoretical and ‘Area under the Curve’ analyses

Abstract

Temporal discounting rates have become a popular dependent variable in social science research. While choice procedures are commonly employed to measure discounting rates, equivalent present value (EPV) procedures may be more sensitive to experimental manipulation. However, their use has been im- peded by the absence of test–retest reliability data. Staff and students at a re- gional Australian university (n = 53) participated in a matching EPV temporal discounting procedure in 2 sessions, 2 weeks apart, completing 30 one-shot, second-price auctions for two amounts, with delays ranging from 1–43 days. Discounting rates were estimated using hyperbolic and exponential models, as well as atheoretical area under the curve (AuC) analyses. Test–retest (relative) stability of the EPV procedure compared favorably with choice procedures (r = .75). Where discounting rates are used as a dependent variable, brief EPV procedures combined with atheoretical analyses of discounting rates are a more sensitive means to detect subtle experimental effects.