3228.0.55.001 - Population Estimates: Concepts, Sources and Methods, 2009  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 12/06/2009   
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Contents >> Data sources >> Births and Deaths

BIRTHS AND DEATHS

9.27 The registration of births and deaths in Australia has been compulsory since the middle of the nineteenth century, when legislation was passed by the various colonies. Since Federation, each state and territory has maintained its own system of registration governed by independent legislation.

9.28 Registration of births and deaths in Australia is a state/territory responsibility rather than an Australian Government responsibility. Each state and territory has its own legislation covering the birth and death registration processes, as well as the roles and responsibilities of the Registrars of Births, Deaths and Marriages (RBDMs).

9.29 While the Registrars have the responsibility of administering the registration process (collection and processing), the ABS is responsible for producing statistics from relevant data. This cooperation between Registrars and the ABS has a long history and has resulted in the availability of a long time series.


Birth registrations

9.30 The process of birth registration is closely linked with the administration of hospitals and maternity clinics where the overwhelming majority of births in Australia take place. Although no national statistics are kept on home births these are believed to comprise a very small portion of all births. By arrangement with the Registrars, birth registration forms are supplied to hospitals and clinics for distribution to parents following the birth of a child.

9.31 Completed registration forms are either sent in by post or delivered to the relevant state or territory Registrar. While some hospitals assist with the dispatch of completed forms to Registrars, most are forwarded through the mail.

9.32 The Registrars are sometimes further assisted by hospitals and clinics which, in addition to distributing registration forms to parents, notify Registrars regularly of births which occur in those institutions. Midwives and doctors are also required to report births which they deliver away from hospitals and clinics. For those births known to Registrars through the notification system and from other sources but not registered within a prescribed time period, the Registrars remind the parent(s) or other qualified informants of their duty to register the birth. Reminders are sent by post to the persons concerned - if there is no response the Registrar may register the birth with the information available. This reminder system together with the general recognition among the population that a birth certificate is an essential identification document, ensures almost complete registration of births.

9.33 Despite this, there are still births which are registered later than the year they occur - of the 285,200 births registered in Australia in 2007, 2% had occurred in 2005 or earlier years.

Perinatal data collection

9.34 Birth registrations are not the only source of births data in Australia. The National Perinatal Statistics Unit of the Australian Institute of Health and Welfare (AIHW) also collects birth data from midwives and other health professional who attend births. These data are published annually in Australia's Mothers and Babies (AIHW 2008).

9.35 Statistics obtained from the Perinatal Data Collection varies from that obtained from birth registrations. For example, the Perinatal Data Collection reported the occurrence of 282,200 live births in Australia in 2006, 5.7% more than the 266,800 live births registered in the same year. The 2007 issue of Births, Australia (cat. no. 3301.0) contains an appendix analysing the differences between birth registrations and the Perinatal Data Collection.


Death registrations

9.36 The primary purpose of death registrations is to allow for the legal identification of persons who are deceased and to ascertain the cause of death. Information about the deceased is supplied by a relative or other person acquainted with the deceased or by an official of the institution where the death occurred.

9.37 As part of the registration process, information on the causes of death is either supplied to the RBDM by the medical practitioner certifying the death on a Medical Certificate of Cause of Death, or supplied as a result of a coronial investigation. Death records are provided electronically to the ABS by individual registrars, on a monthly basis. Information from coronial investigations are provided to the ABS through the National Coroners Information System (NCIS).

9.38 There are three components of a death registration and all components must be completed in order for the RBDM to consider a registration finalised:

  • Death Notification Form - completed by a funeral director, based on information supplied by relatives/friends of the deceased. This form is submitted to the RBDM.
  • Medical Certificate of Cause of Death - this is either completed by a doctor who attended the patient prior to death and forwarded to the RBDM or, if the death is suspicious or due to an unnatural cause (approximately 14% of all deaths), a Coroner will be responsible for investigating and determining the cause of death. Coroners pass this information on to the National Coronial Information System (NCIS) and to the RBDM.
  • Certificate of Burial or Cremation - completed by the funeral director. This form is submitted to the RBDM.

9.39 The ABS only collects a subset of data items from the registration process. Only data items which are required for statistical purposes are forwarded to the ABS by the RBDM.


Preliminary, revised and final estimates

9.40 There are three stages in the production of birth and death estimates for the purpose of compiling population estimates. These result in the production of preliminary, revised and final figures, based on the amount and type of data available at the time the estimates are produced.

9.41 Preliminary population estimates are used for a wide variety of purposes, including the distribution of government funds and services and the determination of each state and territories' number of seats in the House of Representatives (see Chapter 1 - Overview). Due to the importance of these estimates, it is vital that preliminary estimates of all components of population growth produced using limited data (including births and deaths), be as close as possible to those which will be produced at a later date using more complete data.

9.42 Conceptually, estimates of births and deaths used in quarterly post-censal population estimates should relate to the numbers of births and deaths occurring in each particular quarter. However, at the time preliminary population estimates are required (5 to 6 months after the end of each quarter), data to produce occurrence-based estimates are incomplete. Instead, the ABS uses data received from Registrars relating to the numbers of births and deaths registered in a quarter as a proxy for the number of occurrences. These preliminary estimates of births and deaths are based on 'raw' (i.e. unadjusted) counts of registrations for each quarter.

9.43 Preliminary estimates of births and deaths are revised using occurrence data 21 months after the end of each financial year, with adjustments applied to these occurrence-based estimates to reflect known trends in the delay in registration of births and deaths. These adjustments are termed 'inflation factors'. Further information on how these inflation factors are calculated is provided in Chapter 5 - Estimating births and deaths. Revised estimates are released in each September quarter issue of Australian Demographic Statistics (cat. no. 3101.0). For example, revised estimates of births and deaths for the 2006-07 financial year would be released in the September quarter 2008 issue of Australian Demographic Statistics (cat. no. 3101.0).

9.44 Estimates of births and deaths for each intercensal period are finalised after the following five-yearly Census of Population and Housing, based on the latest available occurrence data.


Accuracy

9.45 Information on births and deaths are obtained from a complete enumeration of births and deaths registered during a specified period and are not subject to sampling error. However they are subject to non-sampling error which can arise from inaccuracies in collecting, recording and processing of data. Every effort is made to minimise error by working closely with data providers, the careful design of forms, training of processing staff and efficient data processing procedures.

9.46 Sources of non-sampling error include:
  • incompleteness of an individual record
  • incompleteness of the dataset (e.g. impact of registration lags, processing lags and duplicate records)
  • lack of consistency in the application of questions or forms used by Registrars, both through time and between different states/territories.

9.47 The quality of preliminary births and deaths data, as measured by the differences between preliminary and revised estimates, are affected by delays between the occurrence of these events and their registration. These can be caused by a range of factors, and could include:
  • (in the case of births) delays in parents registering the birth of a child
  • (in the case of deaths) delays in the submission of a death certificate to a registrar
  • delays in the processing of forms at registry offices
  • delays in the processing of data received from registrars at ABS offices
  • other ad-hoc delays or processing problems.

9.48 Preliminary estimates can also be subject to sudden 'shocks', e.g. processing lags due to peak workloads, holiday periods, or technical issues.

9.49 The delays (or lags) in registration are a greater problem for births than for deaths and are the main cause of differences between preliminary and revised estimates of natural increase. More information on these lags, and how adjustments are made to compensate for them, is provided in Chapter 5 - Estimating births and deaths.


Indigenous births and deaths

9.50 Although it is considered likely that most Aboriginal and/or Torres Strait Islander (Indigenous) births and deaths are registered, a proportion of these are not registered as being of Indigenous origin. Birth registrations classify a birth as being of Indigenous origin where at least one parent identified themselves as being of Indigenous origin on the birth registration statement. Death registrations classify a death as being of Indigenous origin where the person completing the registration form (be it a relative or other person acquainted with the deceased, or by an official of the institution where the death occurred) identifies the deceased person as Indigenous.

9.51 There are several data collection forms (including birth and death registration forms) on which information on the Indigenous origin of the person in question is requested. Due to a number of factors, the results are not always consistent. The likelihood that a person will identify, or be identified, as Indigenous on a specific form is known as their propensity to identify as Indigenous.

9.52 Propensity to identify as Indigenous is determined by a range of factors, including:
  • how the information is collected
  • who completes the form
  • the perception of how the information will be used
  • education programs about identifying as Indigenous
  • cultural issues associated with identifying as Indigenous
  • emotional reaction to identifying as Indigenous.

9.53 The way in which a person identifies, or is identified as Indigenous on a specific form can also change over time (this change in propensity to identify as Indigenous is detailed further in Chapter 8 - Estimating the Indigenous population). Together with delays in registration and uncertainty in the first place, these can lead to unexpected changes in Indigenous statistics. Over-precise analysis of Indigenous deaths and mortality should be avoided.

9.54 By linking registered deaths to Census records, the Census Data Enhancement (CDE) project allowed calculation of the expected number of Indigenous deaths. The Indigenous deaths identification rate was then calculated by taking the ratio of the number of deaths reported as Indigenous in death registrations to the number of deaths expected to be recorded as Indigenous in Census using results from the CDE project. The Experimental Life Tables for Aboriginal and Torres Strait Islander Australians, 2005-2007 (cat. no. 3302.0.55.003) publication found that the Indigenous deaths identification rate for Australia in 2006-07 was quite high (around 92%).

9.6 Indigenous deaths identification rates, State/territory and Australia - 2006-07

Number of Indigenous deaths according to death registrations
Expected number of Indigenous deaths(a)
Identification rate
no.
no.
%

NSW
372
427
87.1
Qld
351
372
94.4
WA
254
228
111.4
NT
204
188
108.5
Vic., SA, Tas., ACT, OT
146
226
64.6
Aust.(b)
1 327
1 441
92.1

(a) In Census if weighted PES Indigenous propensities are used.
(b) Includes all states/territories.

9.55 See the Information Paper: Census Data Enhancement - Indigenous Mortality Quality Study, 2006-07 (cat. no. 4723.0) for more information on the CDE project.







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