The ABS sources information about deaths and their causes from the RBDMs in each state and territory. The ABS compiles these data and codes the causes of death to an international standard, called the International Statistical Classification of Diseases and Related Health Problems (ICD). Coding causes of death to an international standard enables the comparability of statistics over time and between countries.

The ICD is revised periodically and currently in its tenth revision (ICD-10). The ICD-10 has been used for Australian causes of death statistics since 1997 and comprises more than 14,000 causes of death and illness; analysis of groups of causes is therefore more manageable than individual causes.

The coding produces an underlying cause – the disease or condition which initiated the sequence of events resulting in death – and, for most deaths, associated causes (any other diseases or conditions that contributed to the death but were not the underlying cause).

Once coded, causes of death can be categorised into disease groupings. Disease groupings are useful for tabulating causes of death in a meaningful way and for examining patterns and trends by cause of death and other important population attributes.

A common method of grouping causes is by ICD chapters (see Table 1). The chapters are arranged according to the type of disease (for example, ‘Certain infectious or parasitic diseases’), the body system affected (for example, ‘Diseases of the circulatory system’) or the circumstance causing death (for example, ‘External causes of morbidity and mortality’, which include injury and poisoning).

For some public health purposes, information about causes of death needs to be more specific; coding causes of death enables identification of specific causes such as influenza, stroke or motor vehicle accident.

There are other methods of grouping diseases that are useful for public health purposes. For example, see Deaths in Australia.

Table 1: International Statistical Classification of Diseases and Related Health Problems 10th revision (ICD-10) chapters
ICD-10 codes Chapter name
A00–B99 Certain infectious and parasitic diseases
C00–D48 Neoplasms
D50–D89 All diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
E00–E90 Endocrine, nutritional and metabolic diseases
F00–F99 Mental and behavioural disorders
G00–G99 Diseases of the nervous system
H00–H59 Diseases of the eye and adnexa
H60–H95 Diseases of ear and mastoid process
I00–I99 Diseases of the circulatory system
J00–J99 Diseases of the respiratory system
K00–K93 Diseases of the digestive system
L00–L99 Diseases of the skin and subcutaneous tissue
M00–M99 Diseases of the musculoskeletal system and connective tissue
N00–N99 Diseases of the genitourinary system
O00–O99 Pregnancy, childbirth and the puerperium
P00–P96 Certain conditions originating in the perinatal period
Q00–Q99 Congenital malformations, deformations and chromosomal abnormalities
R00–R99 Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
S00–T98 Injury, poisoning and certain other consequences of external causes
V01–Y98 External causes of morbidity and mortality
Z00–Z99 Factors influencing health status and contact with health services
U00–U85 Codes for special purposes (including COVID-19)