Shelling (1960) among others have argued that contributions to public goods may be larger if people spread their contributions and give one small contribution at a time. Examining a threshold public good environment, Marx and Matthews (2000) show that multiple rounds may secure a provision level...

We explore the effect of fixed versus dynamic group membership on public good provision. In a novel experimental design, we modify the traditional voluntary contribution mechanism (VCM) by periodically replacing old members of a group with new members over time. Under this dynamic, overlapping...