Table 1.

Example of a data linkage system: core datasets of the WA data linkage system

Dataset	Information Collected (All include some demographic information)	Years of Data	Who Collects Indigenous identity information
Hospital Morbidity Data Set (HMDS)	Patient separations from hospital – reasons for admission, illnesses, details of discharge etc.	1970 -	Hospital administrative staff (Admission clerks, ward clerks)
Mortality Data	Registrar General records information on all deaths in WA including date and cause of death	1969 -	Funeral directors, may be modified by ABS (see Figure 2)
Mental Health Database System (MHDS)	Patient separations from mental health facilities - reasons for admission, illnesses etc.	1966 -	Hospital administrative staff (Admission clerks, ward clerks)
WA Cancer Registry	Notification of incident cancers	1981 -	Diagnosing doctors and laboratories
Midwives Data Collection	Information on all births in WA, only the mother’s Indigenous identity is recorded in relation to the newborn	1980 -	Midwives
Birth Registry Data	Registrar General collects information on all births in WA including data and place of birth.	1974 -	Both parents are required to complete and sign the Birth Registration form
Electoral Roll	Every eligible Australian citizen (18 years or older) is required by law to enrol and vote		Not applicable (i.e. no information on Indigenous status is collected)