3.1 In Australia, the statistical local area (SLA) is the base spatial unit used to collect and disseminate statistics other than those collected from the Census of Population and Housing. In non-Census years, the SLA is the smallest unit defined in the Australian Standard Geographical Classification (ASGC). In aggregate, SLAs cover the whole of Australia without gaps or overlaps. SLAs generally conform to, or combine to form, local government areas (LGAs), statistical subdivisions (SSDs) and statistical divisions (SDs).
3.2 Populations estimates for SLAs are published as at 30 June each year in Regional Population Growth, Australia (cat. no. 3218.0). Estimates by five-year age group and sex are published as at 30 June in Population by Age and Sex, Regions of Australia (cat. no. 3235.0). Population estimates for LGAs, SSDs, SDs, etc. are generally built up from SLA-level estimates.
3.3 The base populations from which subsequent annual estimates are derived are provided by the Census, and are called Census year population estimates. The traditional method used to update these estimates, called the cohort component method, brings forward the population in quarterly steps by ageing the base, then adjusting for subsequent births, deaths and overseas and interstate migration. All estimates at SLA level are constrained to sum to state and territory population estimates.