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Classification criteria

The SSGA18 is designed to meet user needs for social, demographic, and economic statistics.

As such, the geographies: 

  • are useful and relevant for data dissemination at different resolutions 
  • can be aggregated into larger contiguous units
  • are useful building blocks for creating user-defined geographies.

Meshblocks, statistical areas, and urban/rural areas are statistically defined according to these criteria and principles.

Target population size

The population size of statistical areas should be reasonably consistent to ensure comparability. Geographies should have a minimum and maximum population threshold and the range should be minimised as much as possible. The population size of the geographic area should be balanced between releasing detailed information and considering privacy and confidentiality, to ensure that robust statistical outputs can be produced. Near-zero areas (that is, areas with few residents) are appropriate if they fulfil other criteria.

Boundaries relatable to the user

Geographies should represent a ‘community of place’ where people interact together socially and economically.

Boundaries visible on the ground

Boundaries should follow dividing features, such as rivers, roads, railway lines, and lakes. An area should ideally represent a single land use, such as the built-up environment, farm land, forests, or wilderness areas.

Compact shape

The statistical area should be compact and have contiguous boundaries to provide flexible and relevant building block geographies for users, and to assist with data visualisation.

Stable over time

The boundaries of higher-level geographies should remain stable, where possible, to allow the comparison of data over time. However, when the population distribution changes, geographies should be updated to reflect such changes. Boundaries of the smallest geographies should be regularly maintained to reflect real world changes, such as new subdivisions and motorways. 

Additional criteria

Additionally, statistical geographies should: 

  • be well-defined, using objective criteria
  • be mutually exclusive and therefore not overlap
  • be comprehensive, covering the whole area to which the classification applies
  • separate land and water (where possible)
  • separate urban and rural areas (where possible)
  • align to territorial authority and regional council boundaries
  • have clear, objective maintenance criteria and plans that specify criteria for changing boundaries.
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