Step 1: Calculate ED length of stay in hours for each patient.

Step 2: Apply inclusion and exclusion criteria.

Step 3: Sort the cases by ED length of stay from shortest to longest.

Step 4: The 90th percentile is the case where 9 out of 10 complex patients have completed their visits.

Inclusions:

• Admitted patients – Disposition Codes 06 and 07
• Non-Admitted Patients – (Disposition Codes 01, 04 – 05 and 08 – 15) with assigned CTAS I, II, or III

Exclusions:

• ED visits where Registration Date/Time and Triage Date/Time are both blank/unknown (9999)

• ED visits where the MIS functional centre is under Emergency Trauma, Observation or Emergency Mental Health Services (as of January 2015 data)

• Duplicate cases within the same functional center where all ER data elements have the same values except for Abstract ID number

• ED visits where the ED visit Indicator is = '0'

• ED visits where patient has left without being seen by a physician during his/her visit (Disposition Code 02 and 03)

• ED Length of Stay is greater than or equal to 100000 minutes (1666 hours)

• Non-Admitted Patients (Disposition Codes 01 – 05 and 08 – 15) with assigned CTAS IV or V

• Non-Admitted Patients (Disposition Codes 01 – 05 and 08 – 15) with missing CTAS