Core indicators
The metrics that define surgical systems
Sigma is built around the internationally recognised surgical indicators. Member institutions submit values from each hospital and the platform aggregates them across facilities, regions and countries.
Surgical Volume
Procedures / 100,000 / year
The number of surgical procedures performed per 100,000 population each year — a measure of overall surgical activity and access.
Perioperative Mortality (POMR)
Deaths within 30 days
The rate of death within 30 days of a surgical procedure — a core marker of the safety and quality of surgical care.
Workforce Density
SAO providers / 100,000
The number of surgical, anaesthetic and obstetric providers per 100,000 population — capacity to deliver care.
Access to Timely Essential Surgery
% within 2 hours
The proportion of the population that can reach a facility capable of essential surgery within two hours.
Financial Risk Protection
% protected
The share of households protected from catastrophic and impoverishing expenditure due to surgical care.
Capture it all in one place
Authenticated users record these values per facility and Sigma rolls them up automatically.