Testing a Decoy Donation Incentive to Improve Online Survey Participation: Evidence from a Field Experiment

Abstract

This study introduces a new randomized field experiment exploring the impact of offering a decoy charity donation incentive together with a monetary reward to increase response rates in an online survey about coronavirus fears. The study uses a two-stage approach, starting with a preliminary survey to investigate participant attitudes toward different types of donations and an experiment, which added the least desirable £2 donation, from the preliminary survey, as alternative to a £2 Amazon voucher (the target) into the choice set. The study sample consisted of 431 university students. They were split into three groups: a control group with a standard £2 Amazon voucher incentive (216 participants), a decoy group with the target shown first (108 participants), and a decoy group with the decoy shown first (107 participants). We found significantly higher survey completion rates in the decoy group than in the control condition (82.3% vs. 74.5%). Notably, an order effect was observed – presenting the target before the decoy led to a higher completion rate (89.8%) compared to presenting the decoy first (74.8%). Importantly, the inclusion of the decoy incentive did not introduce any response bias. This study confirms previous studies on the decoy effect and enhances our understanding of how a decoy charity donation incentive can positively influence survey participation without negatively affecting response behaviour. It demonstrates the potential of such incentives to encourage participants to complete online surveys, even when a small monetary reward is offered.

Keywords: decoy effect, experiment, donation, survey, incentive