Technical Appendix—Data development—Western Australia (WA)

The HPF was designed to measure the impact of the National Strategic Framework for Aboriginal and Torres Strait Islander Health (NSFATSIH) and will be an important tool for developing the new National Aboriginal and Torres Strait Islander Health Plan (NATSIHP).

Page last updated: 18 December 2012

In WA, Aboriginal and Torres Strait Islander status is collected in a range of health data collections, including the admitted patient data collection, the emergency department data collection, the outpatient care data collection, the Notifiable Disease Data Collection, the WA Health and Well Being Surveillance System, the Midwives Data Collection, the Breast screening Data Collection, the Mental health Information System and the Cancer Registry. It is also stored on ABS Mortality data held by the Department of Health.

The WA Health and Wellbeing Surveillance System (HWSS) asks respondents if they are of Aboriginal or Torres Strait Islander origin. Less than 0.2% reply 'do not know' or refuse to answer the question and the proportion who say that they are Aboriginal and/or Torres Strait Islander ranged from between 3.4% in 2007 to 2.0% in 2009. Reports from the HWSS do not disaggregate results by Aboriginality as they are unlikely to be representative of the Aboriginal and Torres Strait Islander population in WA on a yearly basis, due to the method used to collect the data.

Over the last decade the number of death records with unknown Aboriginal and Torres Strait Islander status registered by the WA Office of Registry of Birth, Deaths and Marriages has represented a substantial proportion of cases. For deaths that have a not-stated identification, status is determined through data linkage by comparing the status of the records of the same individuals in other data sources. Mortality measures are reported by the WA Department of Health, using the enhanced Aboriginal and Torres Strait Islander status field.

Reporting of Aboriginality in Midwives Notification System is based on the mother's Aboriginality; therefore the number of Aboriginal and Torres Strait Islander births recorded is likely to be underestimated. There has been recent agreement to commence the collection of Aboriginal and Torres Strait Islander status of the baby on the WA Midwives Notification of Case Attended form from 1 July 2012.

The Data Integrity Directorate has completed an exercise to compare Aboriginal and Torres Strait Islander status from the Midwives Notification System with and Torres Strait Islander Aboriginal status on the associated hospital records. The study found that there were about 15% less Aboriginal and Torres Strait Islander births recorded among birth registrations than among the Midwives collection of births data. This is because reporting of Aboriginal and Torres Strait Islander Status in birth registration data is non-compulsory.

The elective surgery wait list data collection also includes Indigenous status and this collection is linked to admitted patient records for further verification of Aboriginal and Torres Strait Islander status.

The ABS, the Department of Health Western Australia and the Telethon Institute for Child Health Research have been undertaking a collaborative project that investigated use of data linkage techniques to enhance Indigenous identification on Administrative data. The study utilised the resources of Western Australian Data Linkage System which enables researchers to assess Indigenous identification as recorded across more than ten data sources and more than 40 years. Various methods of deriving Indigenous status were explored and the impact of these methods examined against a selection of health and educational outcomes such as mortality rates, hospitalisation rate and reading and writing scores. A final report is expected to be available late 2012.Top of page