Table 2.

Characteristics of the Ornge data set

Characteristic	Description
Population	Emergent and urgent transport of critically injured patients by Ornge (air and land); includes transport from scene, interfacility transfer and modified scene
Eligibility criteria	Type of transfer = trauma; AND pick-up location (scene or sending facility) located in Waterloo Wellington LHIN, Hamilton Niagara Haldimand Brant LHIN or Halton portion of Mississauga Halton LHIN; OR receiving facility = Hamilton General Hospital or McMaster Children’s Hospital
Data	Basic patient demographic characteristics (age, sex) Call type/scene, interfacility transfers and modified scene Level of priority (dispatch priority, return priority, Canadian Triage and Acuity Scale return priority) Pick-up location (scene/address, hospital) Receiving hospital Vehicle type (Ornge land ambulance, helicopter, local emergency medical service) Crew (number and configuration) Time stamps (call accepted, time call accepted, depart base, time depart base, arrive pick-up landing, arrive time pick-up landing, arrive patient site, arrive time patient site, depart patient site, depart time patient site, depart landing site, depart time landing site, arrive destination land site, arrive time destination land site, transfer care, time transfer care, depart delivery site, time depart delivery site, arrive base, time arrive base)
Indirect identifiers for linkage across data sources	Patient’s name/initials, date of birth and sex, call date, sending facility code, receiving facility code

LHIN = Local Health Integration Network.