The size of a community of practice is important. It needs to be large
enough to allow critical mass but small enough to avoid inhibiting direct
interaction. Experienced practitioners advise that a community with between
20 to 40 members is best able to function smoothly. The actual number
depends on the way in which relationships develop and informal leadership
grows within the community. A less centralized informal leadership of a
community of peers, practitioners and professionals is the preferred structure
since decentralization and informality allow for openness and reciprocity in
interaction.