The methodology applied in selecting the samples of PPP and Traditional projects is crucial to establishing an unbiased test of the relative performances of these approaches. Our sample selection methodology, which is detailed in Appendix B, was guided by the following five criteria:
• Criterion 1 - Projects undertaken since about 2000. We adopted recent projects because this would allow us to focus on PPP and Traditional projects that had been arranged under the current style of policies.
• Criterion 2 - Largely completed projects. We concentrated on completed or largely completed projects so that all or the majority of costs would be brought to account in most projects. All projects included data for at least one of the stages outlined above.
• Criterion 3 - Projects with a significant capex budget. The cut-off for project size was $50 million for New South Wales and $20 million elsewhere.
• Criterion 4 - Similar number of PPP projects to Traditional projects. We sought the population of completed PPP projects in the timeframe and chose traditional projects to broadly match this group.
• Criterion 5 - Projects of similar complexity. We sought to match the PPP and Traditional samples for complexity in respect to 'iconic' buildings, 'greenfield' and 'brownfield' projects.
The full list of projects considered and those selected, together with reasons for rejection is provided in Appendix C.