بررسی مطالعات مشارکت عمومی و خصوصی (PPP) برای پروژه های زیربنایی Review of studies on the public–private partnerships (PPP) for infrastructure projects

1. Introduction Public–private partnerships (PPP) are widely used to deliver a series of infrastructure projects in the world. The PPP approach increases the economic value of infrastructure outputs (Zhang, 2005) and facilitates the overall development of infrastructure (Li et al., 2016b), such as the establishment of transportation infrastructure, sports facilities, water conservancy facilities, and waste-to-energy plants. Alongside the rapidly increasing application of PPP, research interest in the topic has also surged during the last two decades, leading to significant growth in the number of published articles as well as in the diversity of research topics, domains, and methods. The development of the academic body of knowledge on PPP has enabled researchers to share research findings and explore the status quo and trends about the PPP practice; thus, this analysis of articles published in academic journals will assist researchers in exploring the current status and future trends of the chosen topics in this area (Ke et al., 2009). Ke et al. (2009) analysed 170 studies conducted over the period 1998–2008 selected from the following academic journals: Construction Management and Economics (CME), International Journal of Project Management (IJPM), Engineering, Construction and Architectural Management (ECAM), Journal of Construction Engineering and Management (JCEM), Journal of Management in Engineering (JME), Proceedings of Institution of Civil Engineers—Civil Engineering(PICE-CE), and Public Money and Management (PMM). The results of their study showed that the three traditional topics—risk, procurement, and financing— have been expanded over the years to include the following seven research topic categories: investment environment, procurement, economic viability, financial package, risk management, governance issues, and integration research. Marsilio et al. (2011) used bibliometric techniques (citation and co-citation analysis) to analyse articles over the period 1990–2010 from the Social Sciences Citation Index (SSCI) database. Finally, four main clusters were identified—governmental and intergovernmental organizations (IGOs), public administration and public policy academics, scholars studying transaction cost and contract theory, and scholars studying strategy and alliance/network theory. Andon (2012) presented an analysis of relevant PPP literature published up to December 2010 and proposed five research themes that are appropriate for the current PPP research. These themes include the nature of and rationale for PPPs, processes and procedures encouraging the decisionmaking for undertaking PPPs, processes and procedures for expost evaluations of PPPs, merit and worth of PPPs, and PPP regulation and guidance. Neto et al. (2016) used bibliometric methods to study 575 articles related to PPP and its variant, the public finance initiative (PFI), from the Web of Science citation indexing service.