4 Key sources of estimation uncertainty
The key assumptions made concerning the future, and other key sources of estimation uncertainty at the reporting date that have a significant risk of causing a material adjustment to the carrying amounts of assets and liabilities within the next financial year include:
Discount rates used in estimating provisions
The PTA is using market yields on national government bonds with terms to maturity that match, as closely as possible, to the estimated future cash outflows to discount the estimated value of the provisions for annual and long service leave. Fluctuations in the government bond yields may impact the provision for annual and long service leave.
Estimating useful life of key assets
The useful lives are estimated having regard to such factors as asset maintenance, rate of technical and commercial obsolescence, asset usage. The useful lives of key assets are reviewed annually.
The estimated useful life of Freight Network Infrastructure is based on the term of the freight lease.