B . 8 Detailed assumptions and calculations for monetised costs
This section provides the detailed calculations and assumptions used to estimate monetised impacts ( as per Figure 4 ).
B . 8.1 Key model assumptions
The following tables present the key assumptions used to estimate the costs identified for workers , engineered stone PCBUs , other industry PCBUs , governments and suppliers for each prohibition option . This analysis was conducted in May 2023 , and parameter assumptions were current at that point in time .
Table 27 Model specification
Input Assumption Source
Appraisal period
1 July 2023 – June 30 2034 ( includes a 1-year implementation period and 10-year operational period )
Model assumption
Date the prohibition takes effect 1 July 2024 Model assumption Real discount rate 7 % Office of Best Practice Regulation ( Department of Prime Minister and Cabinet , 2020 )
Inflation 3.3 %
Average of forecast CPI at June 2024 , December 2024 and June 2025 ; RBA forecast May 2023 ( RBA , 2023 )
Nominal discount rate 10.5 % Fisher formula Table 28 : Wages , redundancy and PCBU exit costs Input Assumption Source
Average hours of work per week for workers
APS average hours of work per week
38 Australian Bureau of Statistics , 2022 Census of Population and Housing : Income and work data summary , 2021 , Table 12 . Hours worked by age by sex ( ABS , 2022 ) Also these hours are the maximum hours per week permitted under National Employment Standards ( Fair Work Ombudsman , no date )
37.5 APS positions : Australian Public Service Commission ( Australian Public Service Commission , no date )
DECISION REGULATION IMPACT STATEMENT Prohibition on the use of engineered stone Page 90 of 107