Low birthweight is defined as less than 2,500 grams.

Excludes multiple births and stillbirths. 

Analysis by state/territory, remoteness and Socio-Economic Indexes for Areas (SEIFA) Index of Relative Socio-economic Disadvantage (IRSD) is based on usual residence of the mother.

Data excludes Australian non-residents, residents of external territories and records where state/territory of residence was not stated.

Variability bands are to be calculated for single-year and aggregate years data by state and territory using the method below.

Presented as a:

• percentage, and 
• number (for disaggregations by Indigenous status).

100 × (Numerator ÷ Denominator)

Variability bands: to be calculated using the standard method for estimating 95% confidence intervals as follows:

Where   n=number of live-born singleton infants.

CI = confidence interval

CR = crude rate (expressed as a percentage)

2011—Nationally by:

• remoteness (Australian Statistical Geography Standard (ASGS) Remoteness Structure)
• 2011 Socio-Economic Indexes for Areas (SEIFA) Index of Relative Socio-economic Disadvantage (IRSD) deciles

2011—State and territory, by:

• Indigenous status

2009–2011—State and territory, by:

• Indigenous status

Disaggregation by Indigenous status is recommended to be reported using three-year combined data for the current reporting period due to the small number of low birth weight infants born to Indigenous mothers each year. Single year data (2011) will be reported for time-series (state/territory by Indigenous status).

Most recent data available for 2014 Council of Australian Governments (COAG) Reform Council (CRC) report: 2011 (calendar year data).

Indigenous: Aggregated data (2009 to 2011) will be reported for the current reporting period (state and territory).

Single year data (2011) will be reported for time-series (state and territory).

Information is included in the National Perinatal Data Collection (NPDC) for all live births and still births of at least 400 grams birthweight or at least 20 weeks gestation. Indigenous status of infants is currently only available based on the Indigenous status of the mother.

For further detailed analysis by Indigenous status see the CRC National Indigenous Reform Agreement (NIRA) report.

For 2011 data, the 2011 SEIFA IRSD quintile and decile data will be produced using the Australian Standard Geographical Classification (ASGC) geographical unit of Statistical Local Area (SLA). In future years, these data will be produced using the Australian Statistical Geography Standard (ASGS) geographical unit of Statistical Area 2 (SA2).