Australian PPP policy and guidelines are being continually revised in the light of lessons learnt. Recent changes include standardised commercial principles, the taxation of windfall gains and a more scientific approach to risk allocation. Risk transfer is the major driver of value for money outcomes and the wholesale risk transfer of earlier years is being replaced by a systematic approach based on the capacity of the parties to best manage risk at the lowest cost. Independent reviews suggest that risk transfer leads procurement cost savings in the range 12-19% (Regan 2006). Risk transfer significantly outweighs the lower cost of state capital when measured under value for money criteria although this hasn't prevented critics of this procurement method from misrepresenting the cost of capital as the major determinant.