Figure 2. The Sustainable Development Goal (SDG) target and indicator framework developed by the UN subcommittee ^[7].

2. SDGs in the Context of Infrastructure Projects in the Construction Sector

       Most of society’s developments in recent times can be connected to infrastructure projects ^[8][9] and the UN recognise that the development of infrastructure represents a massive opportunity to stimulate economic prosperity, reduce poverty and raise standards in health, education and gender equality ^[10]. It is apparent that ameliorating many of the risks associated with grand challenges, such as climate change, can only be achieved through investment in appropriate and resilient infrastructure and engineering ^[11].

       A growing area of research has been in the comparison of construction projects’ impacts on sustainable development from different angles. For example, Shen et al. ^[12] highlighted the role of projects to impact across the triple bottom line of people, profit and planet ^[13][14][15]. In this regard, construction projects are acknowledged as making an impact on the economic and social development of nations. Increasingly, recognition is given that these dual aims of economic development and social development can be achieved in harmony and, indeed, provide competitive advantage for firms ^[16][17]. Other studies have delved deeper into the changing nature of how project sustainability has changed within the construction industry. For example, Edum-Fotwe and Price ^[18] highlighted the issues that affect the assessment of social factors of construction projects, which this article suggests can be combined with the environmental and economic requirements of projects.

       Defining infrastructure project success is central to understanding how to link global-national level SDGs with local infrastructure projects because it allows stakeholders to align their expectations against shorter-term outputs as well as the longer-term outcomes and SDG impacts. More recent research into project success definition ^[19] has consistently identified benefits and outcomes as being a critical determinant for the assessment of project success. Considering the aforementioned literature, it is possible to synthesise the second proposition related to SDGs in the context of infrastructure projects in the construction sector as follows.

3. Challenges and Opportunities for Measuring SDGs in the Construction Industry

       As discussed above, there is evidence of an increasing interest, and in some cases demand, for promoting SDG measurement in the construction industry ^[8][9], with one report ^[20] that surveyed 325 engineers having a 95% demand from practitioners, who said that this was “very important” to them, with only 30% stating that they had adequate tools, processes and systems to measure them at project level. The survey ^[20] indicated four primary shortfalls for measuring SDGs on infrastructure projects, namely, leadership (1), tools and methods (2), engineers’ business skills in measuring SDG impact (3) and how project success is too narrowly defined as outputs (such as time, cost and scope) and not outcomes (longer-term local impacts and stakeholder value) (4). This highlights that there are several challenges that impede the practical measurement of SDGs on projects, which need to be fully acknowledged.

       Whilst there is still a limited body of research on the limitations of SDG measurement, there is much that can be learned from the measurement of sustainability on projects, and this is transferable to the SDG research. For example, Arif et al. ^[21] identified that there is often limited sustainability knowledge, especially amongst senior leaders, and this results in weaker understanding and impact assessments of related themes, such as poverty, environmental issues, supply chain adherence to sustainability best practice, cultural evaluation, technological deficiencies and limitations of research in depth and breadth, all of which have a negative influence on the valuation of sustainability, both as an investment lens and a delivery approach. A further barrier to the use of SDGs, which potentially mirrors sustainable construction, is what some authors have suggested is a lack of capacity and capability to implement effective and efficient sustainability ^[22]. Considering the aforementioned literature, it is possible to synthesise the third proposition related to SDGs in the context of the challenges and opportunities for measuring SDGs in the construction industry as follows.

4. The Concept of the Triple Bottom Line in Relation to SDGs

       A contribution to the growing literature on the measurement of infrastructure projects on sustainability is provided by Ding and Shen ^[23], who focus on the balance needed between benefits to society whilst protecting the environment and still achieving the economic benefits envisaged in the project business case. The linkage across the three areas in the construction industry is further defined by Kibert ^[17], who suggests that the interrelationship between a project’s outputs and the society that is impacted is a central component of defining the sustainability success of an infrastructure project. This introduces the concept that project success definition needs to consider success against the triple bottom line (TBL) ^[13][14][15] of social, environmental (or ecological) and economic (or financial) effects, otherwise noted as the “three pillars” concept of “people, profit and the planet” ^[13][14][15]. However, the overemphasis on the last of the TBL criteria, namely finance, brings us to the root of the problem of measuring projects’ SDG impact ^[3][4].

       This is because the crux of the project reporting problem lies with the dominance of accounting tools, which have been the preeminent business method of reporting business success for over 500 years since Luca Paccioli first published his papers on double entry bookkeeping ^[24]. It has largely remained unchanged until the past 10 years. As evidence of this widening to cover the three pillars of TBL, there has been a proliferation of mechanisms and economic models to track different elements of TBL, for example, environmental, social and governance (ESG) ^[13], which introduces these three core areas into the business investments decisions that measure the ethical and sustainability impacts of a company. The contention of this current research study is that the proliferation of project success measurement theories, tools and concepts, which are mostly finance-driven, causes confusion and often leads to suboptimal action ^[25] and that a TBL perspective needs to be integrated from the start of any business case development (see later section on business cases). Considering the aforementioned literature, it is possible to synthesise the fourth proposition related to SDGs in the context of the concept of the triple bottom line in relation to SDGs as follows.