Ideally at contract award, the lower bound optimism bias for works duration should be achieved through sufficient risk mitigation if the cost of risk mitigation is less than the cost of managing the residual risk.
Assume that the above applies to this example and the resultant works duration optimism bias is equal to the lower bound optimism bias, 2 %, for non-standard buildings.
If we now consider the example of section 4.3 at contract award ideally the works duration optimism bias after effective management of project risks should be equal to the lower bound optimism bias, i.e. 2 %, for non-standard buildings. In this case the estimated works duration, is approximately 28.6 months, which is calculated as follows:
28 months x (100 % + 2 %) 28.6 months