2.18 A public sector comparator is a part of the financial evaluation of proposed PFI projects. Although not a pass or fail test, it is an aid to forming a judgement about the cost of a proposed PFI deal relative to a conventionally financed project that delivers the same benefits. It can also help a department to understand the economics of PFI bids, since a comparison of the respective costs and revenues can show where and how a PFI bid differs from a conventional procurement. There was, however, no realistic option of proceeding with a conventional public sector procurement for the Laganside Courts project. Nevertheless, the Service commissioned its advisers to produce a nominal public sector comparator. This provided key capital and annual operating costs and helped in the evaluation of the PFI bids.