Abstract This paper examines experimentally the effects of allowing individuals to contribute any desired proportion of their endowments toward a threshold public good. Permitting continuous rather than binary ''all-or-nothing'' contributions significantly increases contributions and facilitates provision. A money-back guarantee further encourages provision, especially when the threshold is high. A high threshold discourages provision in the absence, but not in the presence of a money-back guarantee. High rewards also significantly increase contributions and provision. Sufficiently high rewards elicit convergence of contributions to the threshold, rather than the deterioration towards free riding, often reported in previous studies
