Investigating an Economic Value Metric for Quantifying the Value of Exoskeletons and their Assistance

The data and code provided is used to support and evaluate the conclusions drawn in the paper "Investigating an Economic Value Metric for Quantifying the Value of Exoskeletons and their Assistance". A version of the paper abstract is reproduced here: Current exoskeleton development focuses on achieving physiological improvements, primarily by reducing metabolic rate. However, users cannot yet perceive these metabolic benefits from state-of-the-art exoskeletons. The Marginal Value (MV) metric aims to address this perceptual gap by leveraging behavioral economics to directly measure user experiences. MV quantifies the monetary value added by an exoskeleton to the wearer when walking uphill via sequential Vickrey second-price auctions. During each auction, participants bid the monetary compensation they require to sustain walking for two-minute intervals. The value of exoskeleton assistance is found by comparing bidding trends while walking uphill with and without an exoskeleton. To streamline testing, simulated participants, termed "robo-bidders", engage in the Vickrey auctions alongside a real human participant. We investigate the impact of robo-bidder behavior modeling on participant-reported compensation values and MV. We perform a sensitivity analysis, varying the number of robo-bidders and their bidding behavior (i.e. effort rate), to examine the affect on the outcome MV metric. MV was not significantly affected by the number or behavior of the robo-bidders, although human participant bidding behavior did vary with robo-bidder effort rate. MV also remained independent of subject-specific variables like age and gender. Furthermore, at least 30 minutes of auction participation is necessary for participants' MV to stabilize. While bidding dynamics among auction participants impact human participant behavior, MV as an outcome measure remains independent of this effect. This study highlights the potential of Marginal Value as a comprehensive and personalized metric for evaluating lower-limb exoskeletons.