Blood donation as a public good: an empirical investigation of the free rider problem.

A voluntary blood donation system can be seen as a public good. People can take advantage without contributing and have a free ride. We empirically analyse the extent of free riding and its determinants. Interviews of the general public in Spain (n = 1,211) were used to ask whether respondents were (or have been) regular blood donors and, if not, the reason. Free riders are defined as those who are medically capable to donate blood but do not. In addition, we distinguish four different types of free riding depending on the reason given for not donating. Binomial and multinomial logit models estimate the effect of individual characteristics on the propensity to free ride and the likelihood of the free rider types. Amongst those who are able to donate, there is a 67 % probability of being a free rider. The most likely free rider is female, single, with low/no education and abstained from voting in a recent national election. Gender, age, religious practice, political participation and regional income explain the type of free rider.