Background Clinically significant deterioration of patients admitted to general wards is a recognized complication of hospital care. Rapid Response Systems (RRS) aim to reduce the number of avoidable adverse events. The authors aimed to develop a core quality metric for the evaluation of RRS. Methods We conducted an international consensus process. Participants included patients, carers, clinicians, research scientists, and members of the International Society for Rapid Response Systems with representatives from Europe, Australia, Africa, Asia and the US. Scoping reviews of the literature identified potential metrics. We used a modified Delphi methodology to arrive at a list of candidate indicators that were reviewed for feasibility and applicability across a broad range of healthcare systems including low and middle-income countries. The writing group refined recommendations and further characterized measurement tools. Results Consensus emerged that core outcomes for reporting for quality improvement should include ten metrics related to structure, process and outcome for RRS with outcomes following the domains of the quadruple aim. The conference recommended that hospitals should collect data on cardiac arrests and their potential preventability, timeliness of escalation, critical care interventions and presence of written treatment plans for patients remaining on general wards. Unit level reporting should include the presence of patient activated rapid response and metrics of organizational culture. We suggest two exploratory cost metrics to underpin urgently needed research in this area. Conclusion A consensus process was used to develop ten metrics for better understanding the course and care of deteriorating ward patients. Others are proposed for further development. Results Consensus was achieved for ten RRS quality metrics, of which four were related to improving population health, three to enhancing the patient experience of care, two to cost and one to enhancing provider well-being. Level of recommendations were graded as "essential," "recommended", "optional" and "experimental". Terms used in the formulation of recommendations are described in Table 1. Table 2 provides a summary of specific numerators, denominators and inclusion and exclusion criteria to be used when tracking each entity. We are aware that many hospitals use a multi level activation system; for these institutions, we provide guidance in Table 2 as to which warning level should be used for a given metric. Recommendation 1: Hospitals should measure and track cardiac arrests of regular ward patients Type of metric: Clinical outcome, essential Description of metric: A cardiac arrest is defined as an event in which a patient receives chest compression and/or defibrillation for a non-perfusing rhythm. The definitions of terms used in this and other metrics are presented in Table 1. Rationale: Retrospective reviews of in-hospital cardiac arrests (IHCA) consistently show that signs of deterioration are present for several hours before the even...