Rapid response systems are one of the most widely deployed patient safety interventions in hospitals. Most hospitals maintain some form of RRS, due in part to a 2008 National Patient Safety Goal that required hospitals to maintain a dedicated system for urgent assistance for clinically unstable patients. However, this systematic review and meta-analysis found no definitive evidence that the teams improved in-hospital mortality in adult or pediatric patients. Although RRS usage was associated with decreased cardiac arrest rates on general wards, overall mortality rates did not improve, and the review noted significant problems with the methodological quality of many RRS studies. RRS have proven to be a very popular intervention among nursing staff, and this factor alone may justify implementation of some form of RRS.