Buntman 2002.

Methods	Retrospective cohort, TRISS‐based (Z and M statistic reported)
Participants	People with trauma admitted to 1 of 2 trauma centers in Johannesburg, South Africa, September 1999‐January 2000
Interventions	HEMS vs. GEMS transport to a trauma center
Outcomes	Mortality
Notes	Crew configurations and types of injuries not described
Risk of bias
Bias	Authors' judgement	Support for judgement
Reporting bias	High risk	6/11
External validity	Low risk	3/3
Internal validity	High risk	3/7
Internal validity: confounding and selection bias	High risk	2/6
Power	High risk	0/5