Thus, their personal "tithing," which was induced by the selective benefits they received, paid for
the costs of non-divisible collective goods as a by-product of their membership.23
The value of selective incentives and thus the likelihood of the success of the by-product
strategy for solving the public goods problem and building bridging ties in a group is dependent,
however, on the extent to which competitors can offer the material or non-material goods upon
which they are built. Thus, for example, immigrant ethnic groups in the United States had a
much easier time organizing collectively than do contemporary groups in urban slums because
political entrepreneurs today face more intense competition from government and other service
providers than did their counterparts in the earlier period.24 Similarly, Islamic fundamentalist
organizations in the Middle East and elsewhere have been most successful in attracting new
members when they have little competition in offering meager medical and social services as
selective benefits because they have virtually no competition from other sources.25 The matter of
how political conflict affects the shape of institutional arrangements that determine the value of
one group versus another's selective incentives and, in turn, its capacity to build bridging social
capital will be dealt with in the final section of this paper.
The final strategy for solving the public goods problem is a "federal group." 26 While
large groups cannot induce individuals to make contributions to non-divisible collective goods, a
large group that is a federation of small groups can use the rewards and punishments operative in
the latter to maintain individual contributions to the larger group effort. Olson notes that,
. . . organizations that use selected social incentives to mobilize a latent group interested
in a collective good must be federations of smaller groups. The more important point,
12