The Paradox of Group Size in Collective Action: A Theory of the Critical Mass. II.

Many sociologists incorrectly believe that larger groups are less likely to support collective action than smaller ones. The effect of group size. infact, depends on costs. If the costs of collective goods rise with the number who share in them, larger groups act less frequently than smaller ones. If the costs vary little with group size, larger groups should exhibit more collective action than smaller ones because larger groups have more resources and are more likely to have a critical mass of highly interested and resourceful actors. The positive effects of group size increase with group heterogeneity and nonrandom social ties. Paradoxically, when groups are hetero­ geneous, fewer contributors may be needed to provide a good to larger groups, making collective action less complex and less expensive.