An additional argument is based on

An additional argument is based on distinguishing close, distant, and very distant reviewers. As discussed in section 2.2, close reviewers should have the highest incentive to review nepotistically–to favor close connections on non-scientific grounds–and distant and very distant reviewers should have little to no such incentive. Our co-au-thorship measure enables us to separate reviewers into three groups: “close” (co-authors), “distant” (co-authors of co-authors), and “very distant” (co-authors of co-authors of co-authors or farther). We evaluate the intensity of bias for these three reviewer types by estimating a regression identical to Model 4, except with co-authorship distances treated as a 3-level factor. Table 3 displays estimates from this model.