2.9.1 How an Assessment Is Made


This topic explains the rules the Registrar must follow when making a child support assessment.

Act references

CSA Act section 31, section 66D, section 67, section 68, section 70, section 71, section 72, section 73

CSA Regs regulation 12

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Making an assessment

The Registrar has to make a child support assessment when an application for administrative assessment is accepted. The child support period starts on the day the application was made to the department or to the ATO (unless the payer is a resident of a reciprocating jurisdiction in which case special criteria may apply (2.1.1)) (CSA Act section 31(1)(b) and CSA Regs regulation 12). The Registrar makes a new assessment of child support whenever a new child support period starts, see 2.3.

The Registrar can act on the basis of documents and information in its possession. There is no requirement to conduct any further inquiries or investigations when making an assessment or to seek any further information or documents (CSA Act section 66D).

Child support case includes all assessments for children of the parents

Where parents are assessed for child support for more than one of their children, the Registrar will make assessments for the children taking into account all the assessed children (CSA Act section 67). The assessments together form a single child support case (section 5). This applies even when both parents are eligible carers for one or more of their children, or one or more of the children live with a non-parent carer.

Example: M and F have 3 children, A, B, and C. A lives with M and B lives with F. C lives with a non-parent carer who has applied for M and F to be assessed in respect of C's costs. When working out the child support assessments for the children, the costs of 3 children (as set out in the costs of children (2.4.2) table) are divided by 3 for each child, not the cost of a single child for each child.

This only applies to the children of any 2 parents. When a parent is assessed for child support for children from more than one relationship, there is one child support case for the children from each relationship (CSA Act section 67).

Assessment to relate to whole or part of a single child support period

A child support assessment relates to all, or some of the days, of a single child support period. In other words, an assessment cannot cover more than one child support period (CSA Act section 68). This does not prevent a single notice of assessment from dealing with more than one administrative assessment.

Assessments for part periods

The Registrar can make an assessment that is less than a full child support period (a part period) (CSA Act section 71). This allows assessments to be made where circumstances result in a child support period of less than 15 months.

Validity of assessments

An assessment is still valid even if the Registrar fails to comply with any of the provisions of the CSA Act (CSA Act section 72).

Example: The Registrar fails to advise a parent that they have been assessed to pay child support. The assessment is still valid. It can only be challenged using the provisions set out in the CSA Act and CSRC Act.

In an AAT first or second review or a court appeal under Part IVA of the AAT Act, the validity of an assessment may be affected because the provisions of the CSA Act have not been complied with (see 4.2 and 4.3).

Assumptions as to future events

When making an assessment, the Registrar can assume that facts known at the time of making the assessment will remain unchanged (CSA Act section 73). This allows the Registrar to assume certain facts (e.g. the care arrangements for the child/ren) will apply in the future.


An assessment notice, or a document signed by the Registrar that appears to be a copy of an assessment, is treated as prima facie evidence in legal proceedings. It is evidence that the assessment has been properly made and that the particulars of the assessment are correct (CSA Act section 70(1)), except where a parent applies to the AAT for a review or makes an appeal to a court about the assessment (CSA Act section 70(1A)). In these exceptions the assessment or documents signed by the Registrar are not considered prima facie evidence that all the particulars of the notice of assessment are correct (see 4.2 and 4.3).

Last reviewed: 1 July 2015