We have been requested to test whether PPP projects deliver better results in terms of time and cost outcomes in comparison to Traditional projects. To undertake this task we have established a research methodology that is designed to generate an objective set of data. Of necessity we have had to rely on publicly available data relating to Traditional and PPP projects.
A crucial part of the research design is the methodology employed to select the samples of PPP and Traditional projects. As shown in Figure 3.1, the final sample of 54 projects has a good balance between sectors. The detailed methodological issues of project sample selection, and definitions of terms are provided in detail in Appendix B (Methodology).
In formulating our research methodology to compare the performance of alternative procurement approaches, we kept in mind the recent criticisms levelled at the methodologies applied in the UK studies that have been discussed earlier. In particular, in formulating our detailed research methodology we were mindful that:
• The different project pools we constructed for comparison were not biased by the inclusion of (previously known) overly successful, or under-performing Traditional projects. Similarly, we have not sought to bias the selected project pools by excluding unsuccessful PPP projects.
• We have not selected projects that were atypical and not representative of each procurement method.
• We have not biased our research findings by comparing different baselines between the two procurement methods.
• We have not biased our research findings by comparing different timelines between the two procurement methods.
• We have provided a high degree of transparency in relation to the data and sources applied, so that the research could be fully replicable by others.
By concentrating attention on PPPs undertaken in the eastern states of Australia, we have identified the population of such projects and obtained all publicly available data on them relating to time and cost outcomes relative to budget. We applied five criteria to make the selection of Traditional projects as objective as possible.