Each death registration in the national mortality dataset has 3 dates:
- The date on which the death occurred.
- The date on which the death was registered with the jurisdictional Registry of Births Deaths and Marriages (RBDM).
- The date on which the death was lodged with the ABS.
The time between the occurrence of a death and registration can vary although in general deaths certified by a doctor are registered sooner. Coroner certified deaths undergo extensive investigative processes which can delay registration times, and for this reason they are excluded from the provisional mortality reports.
When looking to measure change over time, the completeness of data for the most recent period is important. When data are received each month by the ABS, the lag between the date of death and date of registration means that only 40-50% of those registrations are deaths that occurred in the month being reported. The remainder are deaths that occurred in earlier months. After a second month of reporting, approximately 95% of doctor certified registrations have been received. This is considered sufficiently complete to enable meaningful comparison with historic counts.
This pattern of registration and reporting is highlighted in the table below, which also shows the slight variation in reporting timelines by cause of death. This should be considered when comparing 2020 data to the 2015-2019 baseline data.