Average length of stay
Average length of stay
Data source
National Hospital Morbidity Database (NHMD)
About the measure
The average (mean) bed days for overnight stays at a public hospital for a given Australian Refined Diagnosis Related Group (AR-DRG) version 6.0x.
Calculating the measure
‘Number of overnight stays’ refers to the number of stays that begin and end on different dates. A stay in hospital may be a complete hospital stay (to discharge, transfer, or death), or a part of the stay if there was a change of care type (for example from acute care to rehabilitation).
‘Total overnight patient bed days’ refers to the sum of the days from the beginning to the end of the stay, for overnight stays.
The average length of stay is calculated as the number of patient bed days for overnight stays divided by the number of overnight stays. The calculation excludes people who were transferred to another health care facility within two days, and people who died in hospital.
Only data which met certain criteria are included in the calculation. The criteria for calculating and presenting results are:
- Stays for acute care
- Stays that begin and end on different dates
- 50 or more overnight stays in the category (in the denominator)
After all the above rules were applied, a small number of exceptionally long stays were excluded as outliers, using this formula:
Outlier bound = 75th percentile + 10 * (75th percentile - 25th percentile)
Stays longer than the outlier bound were excluded. Stays had to be longer than 20 days to be classed as outliers.
Average length of stay is reported for conditions and procedures without complications unless otherwise specified.