Technical notes
Data in this report have been rounded for readability. The following rounding rules have been applied:
- Numbers over 100,000 and under a million are rounded to the nearest multiple of 1,000.
- Numbers between 1,000 and 100,000 are rounded to the nearest multiple of 100.
- Numbers between 500 and 999 are rounded to the nearest multiple of 10.
- Numbers between 100 and 499 are rounded to the nearest multiple of 5.
- Numbers between 10 and 99 are rounded to the nearest whole number.
- Numbers under 10 are rounded to one decimal place.
The following rules apply to the counting of admissions, discharges and length of time for care and protection orders:
- A renewal of an existing order is not counted as an admission. A change to an order is counted as an admission. However, if a new care and protection order is applied in 5 days or less of the discharge of another order (regardless of that type of order), neither an admission nor a discharge are counted.
- If a child is on multiple care and protection orders/ arrangements, all orders/ arrangements must be discharged before a discharge is counted.
- If a child is admitted to, or discharged from, multiple care and protection orders/arrangements, the child is counted for only one admission and/or one discharge for the year.
- The length of time continuously on an order is counted only for the first order/arrangement from which the child is discharged during the year.
- If a child is discharged from an order and a new care and protection order/arrangement is applied in 5 days or less of the discharge, the orders are deemed to be consecutive (that is, the length of time on an order will include both orders).
- Each child is counted for one admission for the year.
Population estimates or Estimated Residential Population (ERP) used in Child Protection Australia (CPA) are sourced from the Australian Bureau of Statistics (ABS). Following each Census, the ABS creates ERPs based on that Census. These include updated time series estimates for previous periods (‘backcast’) and forward periods (‘projections’). The most up to date time series of ERPs from the ABS are used in all trend and rate calculations. CPA 2023–24 uses ERPs based on the 2021 Census, while previous reports use population estimates and projections based on the 2016 Census. This results in differences from data published in previous CPA reports. As such, data from the current CPA publication are not comparable with those from previous releases.
ERPs used to calculate rates are available in the Supplementary data tables P1–P5 (CPA 2023–24: Insights).
Box 1.1: Impacts on population estimates
COVID-19
The COVID-19 pandemic, and the resulting Australian Government closure of the international border from 20 March 2020, caused significant disruptions to the usual Australian population trends. This report uses ERPs that reflect these disruptions.
In the year July 2020 to June 2021, the overall population growth was much smaller than the years prior, and in particular, there was a relatively large decline in the population of Victoria. ABS reporting indicates these were primarily due to net-negative international migration (National, state and territory population | Australian Bureau of Statistics).
This change in usual population trends may result in some rates and proportions being greater than in previous years due to decreases in the denominator (population size) of some sub-populations.
2021 Census and Aboriginal and Torres Strait Islander Peoples
ERPs for Aboriginal and Torres Strait Islander children are sourced from Aboriginal and Torres Strait Islander population projections produced by the ABS. Non-indigenous ERPs are derived by calculating the difference between the total population and the corresponding estimate from the Aboriginal and Torres Strait Islander population projections.
Rates for Aboriginal and Torres Strait Islander children in this report are not comparable to those in previous reports, due to a large increase in Census counts of Aboriginal and Torres Strait Islander peoples between 2016 and 2021. Less than half of this increase was due to demographic factors (births, deaths, migration). The remainder of this increase was due to other (non-demographic) factors, including changes in the propensity of people to identify as an Aboriginal and Torres Strait Islander person.
For further information, see Understanding change in counts of Aboriginal and Torres Strait Islander people and Guide to using historical estimates for comparative analysis and reporting.
This report uses both December and June population data, depending on the point of analysis (see Points of analysis below). December population data are used when calculating rates for during the year counts. June population data are used when calculating rates for 30 June counts.
Population rates are calculated by dividing the number of children for a specific measure or group (for example, children on care and protection orders) by the corresponding population. For example, the rates of children on care and protection orders at 30 June are calculated as follows:

Rates can be compared using a rate ratio, which is one rate divided by another. Rate ratios should be interpreted with care where there are small denominators or where a large proportion of data is recorded as ‘unknown’.
In Child Protection Australia reporting, rate ratios are mainly used to compare Aboriginal and Torres Strait Islander and non-Indigenous rates, and measure the level of Aboriginal and Torres Strait Islander over-representation. Rates are also presented to guide interpretation.
Rate ratios are not calculated where one or both of the rates have fewer than 5 children or young people in the numerator.
Age is always calculated in whole years. For example, a child who was aged 5 years and 9 months is recorded as being aged 5.
Throughout Child Protection Australia, age is calculated at different points in time for a child, depending on the analysis in question:
- For 30 June analyses, age is calculated as at 30 June.
- For analyses of events occurring during the year, age is calculated at the relevant point in time during the year:
- For analyses of children who were the subject of a child protection notification or substantiation, age is calculated at the earliest date of notification during the period.
- For analyses of children who were admitted to, or discharged from, a care and protection order or an out-of-home care placement, age is calculated at the date of first admission and first discharge during the period.
- For analyses of children in contact with the child protection system, age is calculated at the earliest point of contact or at 1 July of the relevant reporting period if the child was on an ongoing care and protection order, or in an ongoing out-of-home care placement at the beginning of the period.
Averages or means are calculated by summing all the values of interest and dividing by the total number of observations of interest. In Child Protection Australia, averages are used in the reporting of the average co-occurrence of abuse and neglect.
Children
The practices used to identify and record the Indigenous status of children vary across states and territories. The quality of the data is therefore unknown.
In this collection, children are counted as Aboriginal and Torres Strait Islander if they are identified as such in the state and territory data collections. Where possible, children whose Indigenous status is recorded as ‘unknown’ are excluded from the calculations of rates and proportions. So, the counts for Aboriginal and Torres Strait Islander children are likely to be an underestimate of the number of Aboriginal and Torres Strait Islander children in the child protection system.
Caregivers
In the out-of-home care data collection, the Indigenous status of caregivers is collected. Carers who are identified as being Aboriginal and Torres Strait Islander are included in the Indigenous category for caregivers. In instances where there is no single caregiver, such as facility-based care, the caregiver will be recorded as Indigenous if the facility is specifically for Aboriginal and Torres Strait Islander children and/or has Indigenous management. However, in CPA: Insights data table S5.12 children are not counted as living with Indigenous caregivers in Indigenous led facility-based care as this is not a preferred placement type under the Aboriginal and Torres Strait Islander Child Placement Principle. If Aboriginal and Torres Strait Islander children are living in other types of facility-based care, the caregiver is not counted as Indigenous.
During the year
Each child is counted only once, even if a child had multiple occurrences of the event during the year.
For example, when calculating the number of children who were the subjects of substantiations of child protection notifications during the year, a child will be counted if a notification received during the financial year was substantiated. However, the child will only be counted once, regardless of how many notifications were substantiated for them in the financial year. Where details relating to the substantiation are reported (for example, type of abuse or neglect, or age of the child) the first substantiated notification is counted.
30 June (at the end of the financial year)
Counts of people at 30 June are calculated by counting each distinct person for whom the event of interest was ongoing at the end of the financial year. Each person is counted only once, even if that person had multiple occurrences of the event ongoing at 30 June.
In instances where a child or young person has multiple child protection orders ongoing at 30 June, the child or young person is counted against the national order type that represented the highest level of intervention.
In instances where a child or young person has multiple living arrangements ongoing at 30 June, the child or young person is counted against the living arrangement type that is considered their usual placement.
For example, when calculating the number of children and young people on a care and protection order at 30 June, a child or young person will be counted if they were on a care and protection order during the reporting period, and the order had not ended, or ended after 30 June. If the child or young person had an ongoing finalised guardianship order and an ongoing interim order at 30 June, they would be counted in the finalised guardianship order category, as this represents the higher level of intervention of the 2 orders.
Trends
Trends are reported as 5-year periods unless specified otherwise. Increases over time in the number or rate of children in the child protection system or children receiving support may relate to legislative changes, such as the expansion of the list of occupations that is mandated to report cases of suspected child maltreatment, or increases in public awareness from inquiries into child protection processes.
It is standard practice to present 5-year trends in data, as changes in state and territory legislation, policy/practice, and information management systems reduce the ability to accurately compare data over longer periods.
Changes that have an impact on the data are provided as caveats to the data, in the Technical notes, and in Appendices B–F.
Child Protection Australia reporting uses the Socio-Economic Indexes for Areas (SEIFA), developed by the ABS to analyse socioeconomic status (ABS 2018).
The SEIFA comprises 4 indexes that are created using information from the Census of Population and Housing. These indexes are:
- the Index of Relative Socio-Economic Disadvantage
- the Index of Relative Socio-Economic Advantage and Disadvantage
- the Index of Economic Resources
- the Index of Education and Occupation.
The Index of Relative Socio-Economic Advantage and Disadvantage is used to compare the average level of socioeconomic advantage and disadvantage. It is the SEIFA index used in this report, ranking geographical areas on a continuum from ‘most disadvantaged’ to ‘least disadvantaged’ using a combination of income, education, employment, occupation, housing, and other Census variables (ABS 2018).
The AIHW uses postcode data to match SEIFA information to child protection data and to calculate population quintiles. The population datasets used to calculate the quintiles for SEIFA were based on regional population data the ABS published in 2023 (ABS 2023b).
For more information on SEIFA refer to Socio-Economic Indexes for Areas (SEIFA), Australia, 2021.
Child Protection Australia reports use the Australian Statistical Geography Standard Remoteness Structure developed by the ABS to analyse the remoteness of a child’s usual place of residence at the time of notification, and the remoteness of a child’s living arrangement (ABS 2021).
The AIHW uses SA2 or postcodes to match remoteness information to child protection data. These data include SA2 / postcode at notification and SA2 / postcode of living arrangement. Some SA2’s and postcodes do not map to single Remoteness Areas. For these SA2’s and postcodes, the data are weighted according to how the population is distributed across the SA2 / postcode and how this overlaps with the relevant Remoteness Area/s. Some children and young people might appear in remoteness areas for which there is no population within that state or territory. This is due to records whose SA2 / postcode is in a different state or territory to the one in which they received a notification, or were in out-of-home care.
For more information on the Australian Statistical Geography Standard Remoteness Structure refer to Australian Statistical Geography Standard (ASGS) Edition 3.
Figure 1 below provides an explanatory guide on how children are classified into the reconnection categories referred to in Table 10.9 of the Child Protection Australia (CPA) 2023–24: Aboriginal and Torres Strait Islander children data tables.
Figure 1: Classification of reconnection categories for CPA 2023–24: Aboriginal and Torres Strait Islander children, data table 10.9
Interactive table showing how Aboriginal and Torres Strait Islander children in out-of-home care (OOHC) are counted into reconnection categories, based on placement changes between the second last and last placement types.
Please note that the proportion of children who are Reconnected is calculated using the Denominator for reconnected, while the proportion of children who are Reconnected or stayed connected is calculated using the Total. Children who are reconnected are counted in both the Reconnected and Reconnected or stayed connected categories. For more information see CPA 2023–24: Aboriginal and Torres Strait Islander children technical specifications.
ABS (Australian Bureau of Statistics) (2011) Socio-economic indexes for areas: getting a handle on individual diversity within areas, September 2011, ABS, accessed 12 April 2025
ABS (Australian Bureau of Statistics) (2018) Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2016, ABS, accessed 12 April 2025.
ABS (Australian Bureau of Statistics) (2021) Australian Statistical Geography Standard (ASGS) Edition 3, ABS, accessed 12 April 2025.
ABS (Australian Bureau of Statistics) (2023a) National, state and territory population, Australia 2024, ABS, accessed 12 April 2025.
ABS (Australian Bureau of Statistics) (2023b) Socio-Economic Indexes for Areas (SEIFA), Australia, 2021, ABS, accessed 12 April 2025.