In the first half of 2011, ClueBot NG – one of the most prolific counter-vandalism bots in the English-language Wikipedia – went down for four distinct periods, each period of downtime lasting from days to weeks. In this paper, we use these periods of breakdown as naturalistic experiments to study Wikipedia’s heterogeneous quality control network, which we analyze as a multi-tiered system in which distinct classes of reviewers use various reviewing technologies to patrol for different kinds of damage at staggered time periods. Our analysis showed that the overall time-to-revert edits was almost doubled when this software agent was down. Yet while a significantly fewer proportion of edits made during the bot’s downtime were reverted, we foun...