Age-specific fertility rates
Age-specific fertility rates are the number of live births (occurred or registered) during the calendar year, according to age of mother, per 1,000 of the female estimated resident population of the same age at 30 June. For calculating these rates, births to mothers under 15 years are included in the 15-19 years age group, and births to mothers aged 50 years and over are included in the 45-49 years age group. Pro rata adjustment is made in respect of births for which age of mother is not given.
Average annual rate of growth
The average annual growth rate, r, is calculated as a percentage using the formula:
where P0 is the population at the start of the period, Pn is the population at the end of the period and n is the length of the period between P0 and Pn in years.
Average household size
Average household size refers to the number of persons per household in private dwellings.
The delivery of a child, irrespective of the duration of pregnancy, who, after being born, breathes or shows any other evidence of life such as heartbeat.
Category of movement
Overseas arrivals and departures are classified according to length of stay (in Australia or overseas), recorded in months and days by travellers on passenger cards. There are three main categories of movement:
A significant number of travellers (i.e. overseas visitors to Australia on arrival and Australian residents going abroad) state exactly 12 months or one year as their intended period of stay. Many of them stay for less than that period and on their departure from, or return to, Australia are therefore classified as short-term. Accordingly, in an attempt to maintain consistency between arrivals and departures, movements of travellers who report their actual or intended period of stay as being one year exactly are randomly allocated to long-term or short-term in proportion to the number of movements of travellers who report their actual length of stay as up to one month more, or one month less, than one year.
- permanent movements;
- long-term movements (one year or more); and
- short-term movements (less than one year).
Death is the permanent disappearance of all evidence of life after birth has taken place. The definition excludes deaths prior to live birth. For the purposes of the Deaths and Causes of Death collections conducted by the ABS, a death refers to any death which occurs in, or en route to Australia and is registered with a state or territory Registry of Births, Deaths and Marriages.
Estimated resident population (ERP)
The official measure of the population of Australia is based on the concept of usual residence. It refers to all people, regardless of nationality or citizenship, who usually live in Australia, with the exception of foreign diplomatic personnel and their families. It includes usual residents who are overseas for less than 12 months. It excludes overseas visitors who are in Australia for less than 12 months.
Estimates of the Australian resident population are generated on a quarterly basis by adding natural increase (the excess of births over deaths) and net overseas migration (NOM) occurring during the period to the population at the beginning of each period. This is known as the cohort component method, and can be represented by the following equation:
P(t+1) = P(t) + B - D + NOM, where:
P(t) = the estimated resident population at time point t
P(t+1) = the estimated resident population at time point t+1
B = the number of births occurring between t and t+1
D = the number of deaths occurring between t and t+1
NOM = net overseas migration occurring between t and t+1.
For state and territory population estimates, an additional term is added to the equation representing net interstate migration occurring between t and t+1, represented by the following equation:
P(t+1) = P(t) + B - D + NOM + NIM.
A household is a group of two or more related or unrelated people who usually reside in the same dwelling who regard themselves as a household and who make common provision for food or other essentials for living; or a person living in a dwelling who makes provision for his or her own food and other essentials for living, without combining with any other person. Households include group households of unrelated persons, same-sex couple households, single-parent households as well as one-person households.
A household usually resides in a private dwelling (including caravans etc. in caravan parks). Persons usually resident in non-private dwellings, such as hotels, motels, boarding houses, gaols and hospitals, are not included in household estimates.
This definition of a household is consistent with the definition used in the census.
Household estimate is a measure of the number of households of the population usually resident in Australia. It is based on the census count of households which is adjusted for missed households, households of overseas visitors, households of Australian residents where all members were temporarily overseas at the time of the census and households of Australian residents where all members were not home on census night and spent census night in a non-private dwelling in Australia.
The household population is the estimated resident population (ERP) that usually lives in private dwellings. It is the ERP less the population that usually lives in non-private dwellings.
Household size refers to the number of persons per household.
An infant death is the death of a live-born child who dies before reaching his/her first birthday.
Infant mortality rate (IMR)
The number of deaths of children under one year of age in a financial year per 1,000 live births in the same financial year.
Intercensal discrepancy is the difference between two estimates at 30 June of a census year population, the first based on the latest census and the second arrived at by updating the 30 June estimate of the previous census date estimate with intercensal components of population change which take account of information available from the latest census. It is caused by errors in the start and/or finish population estimates and/or in estimates of births, deaths or migration in the intervening period which cannot be attributed to a particular source.
Intercensal error is the difference between two estimates at 30 June of a census year population, the first based on the latest census and the second arrived at by updating the 30 June estimate of the previous census year with intercensal components of population change which do not take account of information available from the latest census.
Long-term arrivals comprise:
- overseas visitors who intend to stay in Australia for 12 months or more (but not permanently); and
- Australian residents returning after an absence of 12 months or more overseas.
Long-term departures comprise:
- Australian residents who intend to stay abroad for 12 months or more (but not permanently); and
- overseas visitors departing who stayed 12 months or more in Australia.
The ABS applies a number of adjustments to overseas arrivals and departures data in order to produce estimates of net overseas migration (NOM). These mainly comprise adjustments designed to reflect differences between stated travel intentions and actual travel behaviour, but (in the case of revised NOM estimates) also include adjustments to transform numbers of overseas movements into numbers of travellers. These adjustments are collectively referred to as 'migration adjustments', although they have been referred to in the past as 'category jumping' adjustments.
Excess of births over deaths.
Net interstate migration
The difference between the number of persons who have changed their place of usual residence by moving into a given state or territory and the number who have changed their place of usual residence by moving out of that state or territory during a specified time period. This difference can be either positive or negative.
Net overseas migration
Net overseas migration is net permanent and long-term overseas migration, adjusted for change in traveller duration, intention and multiple movement error.
Net permanent and long-term movement
The difference between the number of permanent (settler) and long-term arrivals and the number of permanent and long-term departures. Short-term movements are excluded.
Overseas arrivals and departures (OAD)
Overseas arrivals and departures (OAD) refer to the arrival or departure of Australian residents or overseas visitors, through Australian airports (or sea ports), which have been recorded on incoming and outgoing passenger cards. Statistics on OAD relate to the number of movements of travellers rather than the number of travellers (i.e. the multiple movements of individual persons during a given reference period are all counted).
Permanent arrivals (settlers)
Permanent arrivals (settlers) comprise:
This definition of settlers is used by the Department of Immigration and Multicultural Affairs (DIMA). Prior to 1985 the definition of settlers used by the Australian Bureau of Statistics (ABS) was the stated intention of the traveller only. Numerically the effect of the change in definition is insignificant. The change was made to avoid the confusion caused by minor differences between data on settlers published separately by the ABS and the DIMA.
- travellers who hold migrant visas (regardless of stated intended period of stay);
- New Zealand citizens who indicate an intention to settle; and
- those who are otherwise eligible to settle (e.g. overseas born children of Australian citizens).
Permanent departures are Australian residents (including former settlers) who on departure state that they are departing permanently.
For Australia, population growth is the sum of natural increase and net overseas migration. For states and territories, population growth also includes net interstate migration. After the census, intercensal population growth also includes an allowance for intercensal discrepancy.
The ABS uses the cohort-component method for producing population projections of Australia, the states, territories, capital cities and balances of state. This method begins with a base population for each sex by single year of age and advances it year by year, for each year in the projection period, by applying assumptions regarding future fertility, mortality and migration. The assumptions are based on demographic trends over the past decade and longer, both in Australia and overseas. The projections are not predictions or forecasts, but are simply illustrations of the change in population which would occur if the assumptions were to prevail over the projection period. A number of projections are produced by the ABS to show a range of possible future outcomes.
Population projections are not predictions or forecasts. They are an assessment of what would happen, in future years, to Australia's population given a set of assumptions about future trends in fertility, mortality and migration.
Short-term arrivals comprise:
- overseas visitors who intend to stay in Australia for less than 12 months
- Australian residents returning after a stay of less than 12 months overseas.
Short-term departures comprise:
Standardised death rate (SDR)
- Australian residents who intend to stay abroad for less than 12 months
- overseas visitors departing after a stay of less than 12 months in Australia.
Standardised death rates enable the comparison of death rates between populations with different age structures by relating them to a standard population. The ABS standard populations relate to the years ending in 1 (e.g. 1991). The current standard population is all persons in the Australian population at June 2001. They are expressed per 1,000 or 100,000 persons. There are two methods of calculating standardised death rates:
Wherever used, the definition adopted is indicated.
- The direct method - this is used when the populations under study are large and the age-specific death rates are reliable. It is the overall death rate that would have prevailed in the standard population if it had experienced at each age the death rates of the population under study.
- The indirect method - this is used when the populations under study are small and the age-specific death rates are unreliable or not known. It is an adjustment to the crude death rate of the standard population to account for the variation between the actual number of deaths in the population under study and the number of deaths which would have occurred if the population under study had experienced the age-specific death rates of the standard population.
State or territory and Statistical Local Area of usual residence
State or territory and Statistical Local Area (SLA) of usual residence refers to the state or territory and SLA of usual residence of:
In the case of overseas movements, state or territory of usual residence refers to the state or territory regarded by the traveller as the one in which he/she lives or has lived. State or territory of intended residence is derived from the intended address given by settlers, and by Australian residents returning after a journey abroad. Particularly in the case of the former, this information does not necessarily relate to the state or territory in which the traveller will eventually establish a permanent residence.
- the population (estimated resident population)
- the mother (birth collection)
- the deceased (death collection).
Statistical District (S Dist)
Statistical Districts (S Dist) consist of selected, significant, predominantly urban areas in Australia which are not located within a Capital City Statistical Division (SD). S Dists enable comparable statistics to be produced about these selected urban areas. Further information concerning S Dists is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).
Statistical Division (SD)
Statistical Divisions (SD) consist of one or more Statistical Subdivisions (SSD). The divisions are designed to be relatively homogeneous regions characterised by identifiable social and economic units within the region, under the unifying influence of one or more major towns or cities. Further information concerning SDs is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).
Statistical Local Area (SLA)
Statistical Local Areas (SLA) are, in most cases, identical with, or have been formed from a division of, whole Local Government Areas (LGA). In other cases, they represent unincorporated areas. In aggregate, SLAs cover the whole of a state or territory without gaps or overlaps. In some cases legal LGAs overlap statistical subdivision boundaries and therefore comprise two or three SLAs (Part A, Part B and, if necessary, Part C). Further information concerning SLAs is contained in Australian Standard Geographical Classification (ASGC)(cat. no. 1216.0).
Statistical Subdivision (SSD)
Statistical Subdivisions (SSD) are of intermediate size, between Statistical Local Areas (SLA) and Statistical Divisions (SD). In aggregate, they cover the whole of Australia without gaps or overlaps. They are defined as socially and economically homogeneous regions characterised by identifiable links between the inhabitants. In the non-urban areas an SSD is characterised by identifiable links between the economic units within the region, under the unifying influence of one or more major towns or cities. Further information concerning SSDs is contained in Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0).
Total fertility rate (TFR)
The sum of age-specific fertility rates (live births at each age of mother per female population of that age). It represents the number of children a female would bear during her lifetime if she experienced current age-specific fertility rates at each age of her reproductive life.