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Hospital Performance: Time patients spent in emergency departments in 2011–12

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Data source

The report uses data from the National Non-admitted Patient Emergency Department Care Database (NNAPEDCD) for the 2011–12 financial year, which was extracted 5 November 2012. This data collection is held by the Australian Institute of Health and Welfare (AIHW).

According to AIHW, the NNAPEDCD is:

a compilation of electronic records of non-admitted patient service episodes from emergency departments of selected public hospitals. Each state and territory health authority determines which hospitals in their jurisdictions submit data to the collection1

The NNAPEDCD is compiled by AIHW from data supplied by Australian state and territory health authorities. This data collection commenced on 1st July 2003, with each collection period covering a financial year.

For more information on the NNAPEDCD, please see the AlHW’s data quality statement at: www.aihw.gov.au/reports/hospitals/australian-hospital-statistics-2011-12-emergency/External link, opens in a new window.

Box 1: Percentage of patients departing ED within four hours of arrival (NEAT)2

Description: The percentage of all ED presentations where the time from presentation to physical departure, i.e. the length of the ED stay, is within four hours. It is calculated for public hospital EDs and measured against progressively increasing targets for states and territories with the objective of 90% of all patients departing ED within four hours of arrival by 2015.

Data source: Data are sourced from the NNAPEDCD (2011–2012), extracted 5 November 2012.

Numerator: Number of presentations where ED stay length is less than or equal to four hours. ED stay length is calculated by subtracting presentation time and presentation date from physical departure time and physical departure date.

Denominator: Number of ED presentations with a physical departure date/time contained within the reporting period.

Computation:
100 x (Numerator ÷ Denominator)

Additional notes:

Presentation time is the earliest recorded time of either the commencement of the clerical registration or the start of the triage process.

Patients who were not admitted use the time the patient’s ED non-admitted clinical care ended in place of the physical departure time.

Patients recorded as did not wait or left at their own risk use the time the patient leaves ED or was first noticed as having left in place of the physical departure time.

Patients who died in the ED or were certified dead on arrival use the time the body was removed from ED. If an ED physician certified the death of the patient outside the ED, then use the time the patient was certified dead.

Performance by states and territories against NEAT is measured against the schedule of progressively increasing targets with the objective of 90% of all patients leaving ED within four hours by 2015. Further detail can be found at About the data - Emergency department services.

Invalid records are excluded from the numerator and denominator. Invalid records are records for which:

  • Length of stay < 0
  • Presentation or triage date or time are missing
  • Physical departure date or time are missing.

Box 2: Time until most admitted patients (90%) departed ED3

Description: The time taken until 90% of admitted patients left the ED. This contextual information includes all patients attending a public hospital ED who were subsequently admitted to the same hospital and measures the total time from presentation until departure at the 90th percentile. There is no national target for this measure.

Data source: Data are sourced from the NNAPEDCD 2011–12, extracted on 5 November 2012.

Computation: Time in ED from arrival to departure (in hours and minutes) at 90th percentile for ED presentations with an episode end status of 1: Admitted to this hospital (either short stay unit, hospital-in-the-home or non-emergency department hospital ward).

Calculation of time in ED: Time in ED from arrival to departure is calculated by subtracting presentations time and date from physical departure time and date respectively, consistent with the business rules included in the NAPEDC National Minimum Data Set 2011–12.

Calculation of 90th percentile: The 90th percentile is calculated using an empirical distribution function with averaging in SAS®4. Using this method, observations are sorted in ascending order.

The calculation is:

n x p = i + f (where i is an integer and
f is the fractional part of n x p).

where

n is the number of observations and
p is the percentile value divided by 100.

If n x p is an integer, then the percentile value will correspond to the average of the values for the ith and (i+1)th observations.

If n x p is not an integer, then the percentile value will correspond to the value for the (i+1)th observation.

For example, if there were 100 observations admitted to the hospital, the 90th percentile will correspond to the average time for the 90th and 91st observations. If there were 101 observations, the 90th percentile will correspond to the time for the 91st observation.

The 90th percentiles have been rounded to the nearest whole number of minutes.

Additional notes:

Admitted patients are those with an episode end status = 1.

Presentation time is the earliest recorded time of either the commencement of the clerical registration or the start of the triage process.

Invalid records are excluded from the numerator and denominator. Invalid records are records for which:

  • Length of stay < 0
  • Presentation or triage date or time are missing
  • Physical departure date or time are missing.

1. Australian Institute of Health and WelfareExternal link, opens in a new window.[http://www.aihw.gov.au/reports/hospitals/australian-hospital-statistics-2011-12-emergency/] - viewed online 7 November 2012.

2. This specification is also used by the Australian Institute of Health and Welfare for publication in Australian Hospital Statistics and for calculating NEAT under the National Partnership Agreement on Improving Public Hospital Services.

3. This specification is also used by the Australian Institute of Health and Welfare for publication in Australian Hospital Statistics.

4. SAS® Institute Inc. 2010. Base SAS® 9.2 Procedures Guide: Statistical Procedures, Third Edition, Cary, NC: SAS Institute Inc.