Deaths that are referred to a coroner can take time to be fully investigated, which subsequently affects the availability of data to the ABS for cause of death coding. Each year, some coroner cases are coded by the ABS before the coronial proceedings are finalised. Coroner cases that have not been closed or had all information made available can impact on data quality as less specific ICD codes often need to be applied.
At the time of coding 2021 data, there was a higher proportion of open coroner cases than at the time of preliminary coding in previous years (67.2% in 2021 versus a 5-year average for 2015-2019 of 56.2%). This is reflected in the 2021 dataset by a higher proportion of deaths due to 'other ill-defined and unspecified causes of mortality' (R99). Cases coded to R99 made up 9.8% of the coroner referred deaths dataset in 2021, compared with a historical average of 6.3% for preliminary data. Of the 2021 coroner referred cases, 74.6% are open cases that fall within the scope of the ABS causes of death revisions process.
Causes of death data for 2021 would ordinarily be revised in early 2024. In light of the information detailed above, an early revision of 2021 data will be conducted during the upcoming revisions cycle in 2023. This revision will target open cases currently coded to 'other ill-defined and unspecified causes of mortality' (R99), 'exposure to unspecified factor' (X59) and 'unspecified event, undetermined intent' (Y34), with the aim of enhancing the specificity of the codes applied to these cases by capturing additional coronial information made available since initial coding.
Causes of death with a high proportion of coroner referred deaths (e.g. suicide, assault and drug-induced deaths) should be interpreted with caution due to the expectation that these data will change during revisions.