Physical Reward Tiers and Backer Behaviour in Social-Impact Crowdfunding

This study examines associations between physical reward tiers and backer behaviour in Kickstarter social-impact campaigns. It distinguishes reward-based crowdfunding, in which backers choose and pay for listed rewards, from unconditional charitable giving. Using 2,034 campaigns and a cleaned tier-level dataset of 15,197 reward tiers, campaign models control for campaign characteristics, logged reward-tier count, and fixed effects for social-impact theme, launch month, and country. The initially positive physical-reward association is not statistically distinguishable from zero after controlling for tier count. Within campaigns, physical tiers are associated with higher logged backer demand. A quadratic specification has a fitted turning point of $7.11 (95% CI: $4.61-$10.73); because the median reward tier is $75, estimated demand is declining across the central observed range. These are conditional associations rather than causal effects.