A commonly quoted Wiccan tradition holds that the ideal number of members for a coven is thirteen, though this is not held as a hard-and-fast rule. Indeed, many U.S. covens are far smaller, though the membership may be augmented by unaffiliated Wiccans at "open" rituals. Pearson noted that covens typically contained between five and ten initiates. They generally avoid mass recruitment due to the feasibility of finding spaces large enough to bring together greater numbers for rituals and because larger numbers inhibit the sense of intimacy and trust that covens utilise.