Relational warm glow and giving in social group

We study charitable giving within social groups. Exploiting a unique dataset, we establish three key relationships between social group size and fundraising outcomes: (i) a positive relationship between group size and the total number of donations; (ii) a negative relationship between group size and the amount given by each donor; (iii) no relationship between group size and the total amount raised by the fundraiser. We rule out classic free-riding to explain these relationships since the number of social group members is only a subset of total contributors. Instead, the findings are consistent with the notion that giving in social groups is motivated by "relational" warm glow.