Rapid response systems (RSS) have been widely endorsed and implemented, but controversy remains regarding their benefit on clinical outcomes. This systematic review of 13 published studies found no overall benefit of RRS on inpatient mortality, cardiac arrests, or unanticipated intensive care unit transfer. As noted in a prior commentary, most published studies had significant methodologic problems that limited their generalizability. While some more recent single-center studies of RRS have achieved impressive results, the authors of this review call for further research into the effectiveness of specific RRS models and the patient populations that may benefit most from RRS availability.