2.73 PSCs are only a broad indication of the cost of a project under conventional procurement. A PSC is based on uncertain estimates of cost and risk and will produce an output that must be understood in the light of such uncertainties. This needs to be taken into account when using PSCs to assess the value for money of a PFI deal. PSCs should be used alongside a range of other information when assessing the value for money of PFI projects.
2.74 Departments need to weigh up the complexity of a financial model against its usefulness and materiality level. An overcomplex model may not produce a more accurate result than a simple one and in addition there is a greater risk that complex models may contain undetected errors.