Out With The Old, In With The New? Unpacking Member Turnover in Online Production Groups

Nearly any group is subject to \textit{turnover}: some people leave, while others join. Turnover can be especially high in online groups, since participation typically is strictly voluntary. We investigated the effects of member turnover in online groups, specifically in Wikipedia's WikiProjects. We based our studies on theories from organizational science, which suggest that it is not just the amount of turnover, but the \textit{characteristics} of those leaving and those joining that matter. We characterized leavers and newcomers by their prior productivity, tenure (in the group or community), and participation in other groups within the larger community. Furthermore, we considered the moderating effect of group size on turnover. We analyzed data from 88,427 editors who participated in 1,054 WikiProjects, finding that (1) the positive effects of newcomers to a group were larger than the negative effects of leavers, (2) prior productivity, tenure, and participation in other groups all played significant roles, and (3) the effects of leavers and newcomers were amplified in larger groups.