Hospital admissions data were extracted from the Victorian Admitted Episodes Dataset (VAED), which records all admissions to public and private hospitals in the state of Victoria. The VAED includes demographic, clinical and administrative details for every admitted episode of care occurring in these hospitals. The coding in the VAED conforms to the definitions in the National Health Data Dictionary (NHDD) (Australian Institute of Health and Welfare, 2015). Population and Local Government Areas (LGA) geographical data are sourced from the Australian Bureau of Statistics (ABS).

Episode selection for incidents

• Victorian hospital admissions recorded on the VAED occurring 1 January 2006 to 31 December 2018, coded according to the Fourth-Tenth Editions of ICD-10–AM (NCCH; 2004, 2006, 2008, 2010, NCCC;2013,ACCD; 2015, 2017).
• Episodes with an external cause of morbidity in the ICD-10-AM range V00-X59 (i.e. unintentional section of Chapter 20 External causes of morbidity and mortality).
• Episodes with a community injury in the ICD-10-AM range S00-T75 or T79 in principal diagnosis code.
• Mode of admission can have any value except those indicating that a transfer from another hospital has occurred or that the record is a ‘statistical separation’- a change of care type within a hospital. These admissions are excluded to reduce over-counting of cases and to provide an estimated incidence of admission.
• Patients admitted for day-treatments for the same injury within a course of 30 days, with an admission type indicating it was a “planned” admission were removed. These included for example procedures such as hyperbaric oxygen therapy.

Episode selection for bed-days

• Each record in the VAED refers to a single episode of care in a hospital. Some injuries result in more than one episode in hospital and therefore more than one VAED record. Therefore, for injury incident estimates, transfers within and between hospitals, as well as rehabilitation admissions and those admitted for planned day-treatments, were excluded. These episodes, however, were included when providing estimates of injury-related bed-days.
• Episodes with a principal diagnosis as an injury in the ICD-10-AM code range S00-T75.9, T79-T79.9, T89-T98.99 (these codes exclude medical injury).

For the purposes of the Injury Atlas, injury hospitalisation cases of Interstate/Overseas/Unknown and Victoria-unincorporated residents were excluded in data outputs. The age groups are defined as follows to match those in the National Injury Prevention and Safety Promotion Plan. A child is defined as a person aged 0-14 years, an adolescent and young adult is a person aged 15-24 years, an adult is a person aged 25-64 years and an older adult is a person aged 65 years and above.

Hospital admission rates per 100,000 population for selected causes and age groups and gender and by admission or financial year and LGA were calculated using population data. By default, the injury count/rate by LGA is presented in five groups using the quantile method. The reclassify option in the map allows user to change number of groups and reclassify using other methods such as natural Jenks, equal interval and standard deviation methods.