The PCC is just one way of exploring the possibility of public sector involvement and assessing their value for money. Furthermore, the PCC only provide a partial picture. It is impossible to determine from only the public cost assessment whether a PPP will be beneficial without the comparative factor of what it would cost the private sector.
Parker Williams whose PPP experience includes serving Administrator of the Maryland State Highway Administration and Deputy Secretary of Administration with the Pennsylvania Department of Transportation, agrees noting the importance of the PCC while also pointing to its limitations. Having had several successful transportation PPPs, Williams notes that decision making for a PPP revolves around a host of issues including sufficient state and local government funding without financing from the private sector, a possible revenue source generated by the project to offset the cost of private sector involvement and financing, and scheduling delays resulting from lack of funds in the public sector. For these reasons as well as the need to be cautious and not overly biased as explained the previous best practice, Parker notes that it is important to view the with caution PCC as a "decision aid tool, not a decision making tool."67
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67 Parker, W. (2011, March 10). Telephone interview.