Learn about our approach to determining the behavioural assumptions we apply when estimating the cost of policy proposals.

Costing Concepts explain how the PBO thinks about budget mechanics, reporting frameworks, and general methodology in costing policy.

Parliamentarians and parties must be involved in any costing activity for policies attributed to them.

Learn about the factors affecting uncertainty in costings and how the PBO deals with them.

Information for Commonwealth agencies who work with the PBO.

How and when broader economy‑wide effects, also referred to as second round effects, are captured in policy costings.

Why and how the PBO rounds its estimates of the financial implications of policy proposals.

How public debt interest (PDI) is treated in PBO costings.

PBO costings don't include the possible impact of any provisions in the Contingency Reserve.