Why are deaths data important?

Looking at how many people die and what caused their death can provide vital information about the health of a population. Examining patterns and trends in deaths can help explain differences and changes in the health of a population, contribute to the evaluation of health strategies and interventions, and guide planning and policy-making.

Cause-specific death statistics provide insight into the events that contribute to deaths and to the burden of disease. Causes of death are documented on a death certificate and can be classified into disease groups. The coding of death certificates produces an underlying cause and, for many deaths, one or more associated causes of death.

Underlying, associated, and multiple causes of death

Death statistics are often based on the underlying cause of death only—that is, the disease or injury that initiated the train of events leading directly to death, or the circumstances of the accident or violence that produced the fatal injury. Analysis of the underlying cause of death is important because it points to where interventions can be targeted.

Leading cause of death statistics presented here are based on the underlying cause of death.

Associated causes of death are all causes that contributed to the death, other than the underlying cause of death. They include the immediate (or direct) cause (the condition that occurred immediately before death or closest to the time of death), any intervening causes, and conditions which contributed to the death but were not related to the disease or condition causing the death. Analyses using associated causes of death offer insight into the disease processes occurring at the end of life or, for injury causes of death, the nature of the injury.

Multiple causes of death statistics are based on both the underlying and associated causes of death.

Changes in the pattern of causes of death may reflect changes in behaviours, exposures to disease or injury, social and environmental circumstances, the effects of medical and technological advances, as well as data coding practices.

Year of occurrence and year of registration

Trends may be presented by year of occurrence of death or year of registration of death.

Using year of occurrence of death is common when the exact time period of the death is important (for example, seasonal deaths) however the latest data available underestimates the occurrence of recent deaths due to a lag in registration.

For this reason, year of registration of death is often used to allow the latest year of data to be compared to previous years.

In both cases the latest year of data are coded with preliminary causes of death information and may underestimate causes of death that are usually certified by a coroner (for example, external causes of death including suicide).

Unless otherwise specified, deaths statistics presented here are based on year of registration of death.

For more information on how deaths are registered, coded and updated, see About deaths data.