12/16 month rule
A method for measuring an overseas traveller's duration of stay or absence which takes an approach to measure usual residence that does not have to be continuous, as opposed to the continuous approach used under a '12/12 month rule'. Under a '12/16 month rule', incoming overseas travellers (who are not currently counted in the population) must be resident in Australia for a total period of 12 months or more, during the 16 month follow-up period to then be included in the estimated resident population. Similarly, those travellers departing Australia (who are currently counted in the population) must be absent from Australia for a total of 12 months or more during the 16 month follow-up period to then be subtracted from the estimated resident population.
The 12/16 month rule therefore takes account of those persons who may have left Australia briefly and returned, while still being resident for 12 months out of 16. Similarly, it takes account of Australians who live most of the time overseas but periodically return to Australia for short periods.
The dependency ratio is a measure used to compare the size of the working age population to the size of the non-working age population, calculated as the sum of people aged 0-14 and 65 years and over (that is, 'dependents') divided by the number of people aged 15-64 years, multiplied by 100.
Age-specific death rates
Age-specific death rates, or mx, are the number of deaths (on either an occurred or registered basis) during the calendar year at a specified age per 1,000 of the estimated resident population of the same age at mid-point of the year (30 June). Pro rata adjustment is made in respect of deaths for which the age of the deceased is not given.
Age-specific fertility rates
Age-specific fertility rates in this publication are the number of live births (on either an occurred or registered basis) during the financial year, according to the age of the 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.
Average annual growth rate
The average annual population 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 Pn and P0 in years.
Baby boom refers to the generation born between the end of World War II and the mid-1960s. Baby boomers are usually taken to be those born in the years 1946 to 1965 inclusive.
Balance of State
Within each state and territory, the area not defined as being part of the Greater Capital Statistical Area is represented by a Balance of state region. These are the same as 'Rest of state' in the GCCSA Structure of the Australian Statistical Geography Standard (ASGS). For more information, please refer to Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011 (cat. no. 1270.0.55.001).
The delivery of a child, irrespective of the duration of pregnancy, who, after being born, breathes or shows any evidence of life such as a heartbeat.
Refers to the Greater Capital City Statistical Areas of states and territories as defined in the Australian Statistical Geography Standard. For more information, please refer to Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011 (cat. no. 1270.0.55.001).
Estimated resident population
The official measure of the population of Australia is based on the concept of residence. It refers to all people, regardless of nationality or citizenship or legal status, 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 over a 16 month period. It excludes overseas visitors who are in Australia for less than 12 months over a 16 month period.
A fertility schedule is a time series of age-specific fertility rates.
Greater Capital City Statistical Area (GCCSA)
Represent the socioeconomic area of each of the eight state and territory capital cities. These boundaries are built from aggregations of whole Statistical Areas Level 4. GCCSA boundaries represent a broad socioeconomic definition of each capital city, they contain not only the urban area of the capital city, but also surrounding and non-urban areas where much of the population has strong links to the capital city, through for example, commuting to work.
Infant mortality rate
The number of deaths of children under one year of age in a calendar year per 1,000 live births in the same calendar year.
The difference between the number of persons who have changed their place of usual residence by moving into a defined geographical area and the number who have changed their place of usual residence by moving out of that defined geographical area during a specified time period. This difference may be either positive or negative.
Life expectancy refers to the average number of additional years a person of a given age and sex might expect to live if the age-specific death rates of the given period continued throughout his or her lifetime.
A life table is a statistical model used to represent the mortality experience of a population. In its simplest form, a life table is generated from age-specific death rates and the resulting values are used to measure mortality, survivorship and life expectancy. The life table functions relevant to population projections are:
- qx - the proportion of persons dying between exact age x and exact age x+1. It is the mortality rate, from which other functions of the life table are derived; and
- ex - life expectancy at age x.
For any distribution the median value (age, duration, interval) is that value which divides the relevant population into two equal parts, half falling below the value, and half exceeding it. Where the value for a particular record has not been stated, that record is excluded from the calculation.
The 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 (NOM)
Net overseas migration is the net gain or loss of population through immigration to Australia and emigration from Australia. Under the current method for estimating final net overseas migration this term is based on a traveller's actual duration of stay or absence using the '12/16 month rule'. Preliminary NOM estimates are modelled on patterns of traveller behaviours observed in final NOM estimates for the same period one year earlier. NOM is:
- based on an international travellers' duration of stay being in or out of Australia for 12 months or more over a 16 month period;
- the difference between:
- the number of incoming travellers who stay in Australia for 12 months or more over a 16 month period, who are not currently counted within the population, and are then added to the population (NOM arrivals); and
- the number of outgoing international travellers who leave Australia for 12 months or more over a 16 month period, who are currently counted within the population, and are then subtracted from the population (NOM departures).
NOM arrivals are all overseas arrivals that contribute to net overseas migration (NOM). It is the number of incoming international travellers who stay in Australia for 12 months or more over a 16 month period, who are not currently counted within the population, and are then added to the population.
Under the current method for estimating final net overseas migration this term is based on a traveller's actual duration of stay using the '12/16 month rule'.
NOM departures are all overseas departures that contribute to net overseas migration (NOM). It is the number of outgoing international travellers who leave Australia for 12 months or more over a 16 month period, who are currently counted within the population, and are then subtracted from the population.
Under the current method for estimating net overseas migration this term is then based on a traveller's actual duration of stay or absence using the '12/16 month rule'.
Other Territories comprises Christmas Island, Cocos (Keeling) Islands and Jervis Bay Territory.
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 difference.
Rate of population growth
Population change over a period as a proportion (percentage) of the population at the beginning of the period.
Replacement level fertility is the number of babies a female would need to have over her reproductive life span to replace herself and her partner. Given the current mortality of females up to age 49 years, replacement fertility is estimated at 2.1 babies per female.
The sex ratio relates to the number of males per 100 females. The sex ratio is defined for total population, at birth, at death and among age groups by appropriately selecting the numerator and denominator of the ratio.
Standardised death rate
Standardised death rates enable the comparison of death rates between populations with different age structures by relating them to a standard population. The current standard population is all persons in the Australian population at 30 June 2001 (19,413,240), as published prior to recasting the ERP series. SDRs are expressed per 1,000 or 100,000 persons. The direct standardisation method was used to calculate standardised death rates.
Statistical Area Level 4 (SA4)
An area defined in the Australian Statistical Geography Standard designed for the output of labour force data and to reflect labour markets. In rural areas SA4s generally represent aggregations of multiple small labour markets with socioeconomic connections or similar industry characteristics. Large regional city labour markets are generally defined by a single SA4. Within major metropolitan labour markets SA4s represent sub-labour markets. SA4s are built from whole Statistical Area Level 3 regions. They generally have a population over 100,000 people to enable accurate labour force survey data to be generated. There are 88 SA4s and they cover the whole of Australia without gaps or overlaps. For more information, please refer to Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011
(cat. no. 1270.0.55.001).
Total fertility rate
The sum of age-specific fertility rates (live births at each age of mother per female population of that age) divided by 1,000. 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 (ages 15-49).
Usual residence within Australia refers to that address at which the person has lived or intends to live for a total of six months or more in a given reference year.