In one embodiment, a method comprises accessing a physician-referral-network, which comprises a number of nodes and a number of edges connecting the nodes, each of the edges representing a single degree of separation between the nodes. Each node represents a physician, and each edge represents a patient-referral between two physicians corresponding to the connected nodes. One or more references indicating a patient-referral from a first physician to a second physician is received. The physician-referral-network is updated based on the received reference. One or more performance-scores from the second physicians may be received, each performance-score corresponding to a patient-referral. A referral-score is calculated for the first physician based on the performance-scores. The method further comprises determining if a referral-score for a first physician is below a threshold referral-score.