Key Portfolio Selection Criteria for Sustainable Construction

Abstract

Selecting the best projects and programs is of paramount importance to the success of organizations in the construction industry for the employer, clients, and developers. The existing selection criteria in the literature are tailored toward traditional construction projects. However, with the current move toward sustainable construction, there is a need to incorporate sustainability-specific criteria in the process portfolio selection. This study aims to identify and evaluate the sustainability-specific project selection criteria for construction organizations from the client’s perspective; this research topic is significant because developers/clients do not always consider sustainability criteria when selecting their portfolio of projects. The research methodology of this study consists of a literature review, identifying the sustainability criteria into an integrated list, and a survey to weight and rank the criteria. Sixteen criteria were identified through an extensive review of the related literature. These criteria were categorized based on three sustainability pillars: environmental, social, and economic. The environmental pillar includes six selection criteria, which are energy use, material use, water use, land use, pollution, and waste management. The social pillar consists of five selection criteria, which include health and safety, employee training and education, improvement in infrastructure, relation with local communities, and alternative transportation. The economic pillar consists of five selection criteria, which include life cycle cost, contribution to GDP, employment creation, innovation and technology, and use of national suppliers. A survey was developed and circulated to specialists in the construction industry in the United Arab Emirates (UAE). The weights for the sustainability selection criteria were assessed by using the Analytic Hierarchy Process (AHP) method. The results show that the environmental group is the most important group among the pillars of sustainability, with a weight of 0.520, compared with the social and the economic pillars, which had weights of 0.214 and 0.266, respectively.

1. Introduction

The devastating impacts of construction processes, including the generation of waste and dust, air and water pollution, and energy consumption, have raised many concerns recently. The construction industry’s role in a community’s economy, society, and environment cannot be ignored. With the current shortage of natural resources, increase in climate change, and destabilized environment, there is an increasing need for sustainable construction and development. The assessment and evaluation of sustainability indicators in construction projects are essential for stakeholders and decision makers. There is an increasing need for organizations to integrate sustainability criteria in their portfolio decision-making process. The management of construction projects significantly impacts a nation’s environmental, societal, and economic dynamics. Thus, it is important to explore various methods to include sustainability and its valuable indicators in portfolio management and strategies [1].

Making sustainability-conscious decisions in the management of construction projects is one of the biggest challenges facing organizations. Sustainability has become a common element in many organizations’ mission statements and business strategies. McKinlay [2] mentioned that the growth development of the project management profession requires project managers to be in charge of sustainability. Project management professionals have gradually understood the growing need to develop tools and methods to incorporate sustainability benefits and strategies with project management. Even as sustainability becomes popular in portfolio management, its incorporation, especially the assessment of sustainability in construction projects, is still a debatable topic [3]. Therefore, there is a requirement to develop sustainability assessment mechanisms in construction projects bearing in mind that sustainability combines indexes and indicators to evaluate various aspects of sustainability in portfolio management [4,5,6].

Globally, organizations are looking for sustainable development methods to reduce natural resource use in order to create an equilibrium between natural resources, urbanization, and growth. The selection of criteria should be assessed based on three pillars of sustainability to address all aspects of sustainable development. The concept of sustainability can be considered within each project value or as a business strategy within an organization. Sustainability can be linked to an organization’s mission, vision, and objectives or implemented at the project level. As sustainable construction is derived from sustainable development concepts, it should address the three sustainable development bottom lines. The commonly quoted sustainable development definition is one “that meets the needs of the present without compromising the ability of the future generations to meet their own needs” [7]. The three sustainability pillars of environmental, social, and economic have to be balanced [8]. Edum-Fotwe and Price [9] argue that a company’s state of sustainability can be referred to as first order, second order, or third order due to considering one pillar, two pillars, or three pillars, respectively. Thus, sustainable construction is also interpreted as first-, second-, or third-order states of sustainability [10]. Kibert’s [11] definition of sustainable construction focuses on a company’s ability to use its resources and ecological principles in responsible development and management of a healthy environment.

Sustainability aims at achieving a more equitable and wealthy society where there is conservation of the cultural practices and environment for the benefit of future generations [12]. Thus, international companies should commit to implementing sustainable strategies to conserve the environment [13]. Companies are expected to incorporate strategies that ensure clean products and production processes that do not harm the environment. Companies have also realized the economic benefits of a clean environment. While adhering to environmentally safe strategies, companies should protect their employees’ concerns, maintain and enhance an ethical image, adhere to government directives, and develop new opportunities in order to maintain a competitive edge [14].

Traditionally, project selection in the construction industry has focused on budget, time, risks, resource allocation, and financial factors, while the significance of the sustainability benefits was not considered. Due to the increasing significance of sustainability, it has become important to study and analyze the value of sustainability in the process of project selection. Failure to include the sustainability value in the selection process negatively impacts the value of a portfolio. Clients need to evaluate sustainability based on the three pillars of environmental, social, and economic when conducting their portfolio evaluations. Moreover, clients should select the most appropriate projects based on those that increase the sustainability value of their portfolio by reducing negative environmental and social effects. This promotes the need for clients to consider reliable sustainability selection criteria in portfolio selection process [15].

The development of new project selection criteria based on sustainability benefits has become significant. Currently, decision makers concentrate on selecting their projects by considering specific criteria to increase benefits and advantages for stakeholders. However, there is a need to include sustainability benefits in the decision-making process, which helps to relate the organization’s strategies and project benefits to individual project deliverables. This study aims to identify and assess the key sustainability-specific criteria for the selection of construction projects.

2. Literature Review

The Brundtland Report brought the sustainability debate to the global fore when it proposed that development must not interfere with human needs and satisfaction [16]. Many industrial practices have potentially adverse effects on human health and future generations, resulting in efforts to change these poor practices [17]. Sustainability in the business field refers to the act of meeting the needs of an organization’s stakeholders without losing its ability to meet the needs of its future stakeholders [18]. Moreover, Szekely and Knirsch [19] define business sustainability as expanding economic growth, prestige, customer satisfaction, corporate reputation, shareholder value, and the quality of products and services a business offers. This means that a business should adopt appropriate ethical practices, develop sustainable employment opportunities, attend to overlooked needs, and build value for the stakeholders. Companies and organizations have been criticized for not paying adequate attention to their environmental and social impacts due to the lack of knowledge in sustainability development [20]. Economic success is also affected by a lack sustainability practices as social and environmental issues affect both its costs and income [21]. Even though more research is required to confirm this, companies operating in an environmentally clean environment are associated with higher financial success. King et al. [22] illustrated the association between reduced pollution and higher income and noted that a company with good environmental performance relative to the industry is associated with higher financial success. In the same breath, other scholars confirm that firms also experience better financial performance when adopting discretionary environmental change [23]. With the continued sustainability debate among business entities, organizations need to understand what sustainable business operation entails. It is also significant to understand how businesses can best integrate sustainability indicators into their decision-making process in order to address their operations’ social and environmental impacts; such actions can help businesses avoid becoming obsolete [24].

Sustainable buildings refer to buildings that involve all the sustainability indicators and other technical aspects [25]. There is no currently explicit recognition or categorization approach for sustainable buildings and scholars are still debating how to measure building sustainability [26]. Regulations were crucial in building energy rationing after the energy crisis in the early 1970s when energy consumption measurement became the sustainability measure for assessing buildings. With the gradual growth and development of sustainability consciousness among professionals, energy consumption is just one factor among other measurement criteria. Due to the complexity of buildings, a multi-disciplinary approach is recommended in assessing building sustainability [27]. Building sustainability is considered complex because of the use of various technologies brought together through different processes. Therefore, a building’s sustainability must focus on unique techniques employed to unlock every functional unit and the whole building. As buildings cannot exist in solitude, assessing the surrounding environment is crucial in determining the overall building sustainability [27].

There are many multi-criteria designs for ensuring sustainability. The United Kingdom was the first to introduce a multi-criteria system for sustainability, BREEAM, which was launched in 1993 by the Building Research Establishment (BRE). The industry has since dramatically adopted the BREEAM system, which has gained worldwide recognition and has also been adapted to other criteria from countries such as Canada, Australia, and Hong Kong. The BREEAM system evaluates different categories, including water availability, transport, materials, ecology, energy, pollution, health, management, land use, and innovation [28]. Another system that is becoming popular is Leadership in Energy and Environmental Design (LEED), which was developed in the year 1998. According to its six evaluation categories, the system awards points to each category. These categories include 14 points for the sustainable site, 5 points for water efficacy, 17 points for energy and atmosphere, 13 points for materials and resources, 15 points for indoor environment quality, and 5 points for innovation and regional specificities [29]. The Comprehensive Assessment System for Building Environmental Efficiency (CASBEE) refers to a Japanese building rating system developed in 2001. It employs different assessment tools based on a life cycle evaluation. This design is founded on closed ecosystems and focuses on two assessment levels: building performance and environmental load. Building performance covers resources and materials, energy, and the outdoor environment. Environmental load covers criteria such as reuse and sustainability of materials and resources and the surrounding environment. Compared with the two previously discussed approaches, the CASBEE graphically presents its results as a measure of eco-efficiency. The environmental loads are displayed on one axis and quality is presented on the other axis. The CASBEE identifies sustainable buildings as having the lowest environmental load and highest quality. Despite its immediate acknowledgment, only about 100 buildings have received the CASBEE certification [30]. Toward the end of the 1990s, Natural Resources Canada (NRC) was mandated to lead in the internationalization of rating systems by the Sustainable Building Council [31]. While adapting the Canadian version of BREEAM, the Green Building Initiative (GBI) launched the Green Globes green building certification system [31]. The criteria of the Green Globes system include site, project management, indoor environment, resources, water, energy, solid waste, and building materials [31].

Fernandez-Sanchez and Rodriguez-Lopez [24] suggested a model for identifying sustainability indicators in the construction industry and developed a list of thirty macro-indicators for the sustainability valuation of an infrastructure project. Shen et al. [25] and Huang and Hsu [32] proposed similar models that helped identify the sustainability indicators of construction projects using different approaches. Huang and Hsu [32] identified thirty construction project sustainability indicators derived from relevant research literature and government rules. Shen et al. [26] used the study reports of eighty-seven construction projects in China to identify thirty-four indicators that relate to the sustainability of four types of construction projects. Most of the works adopted the three-pillar perspective of the environmental, social, and economic sustainability factors of construction projects. Several important issues should be considered in developing an appropriate sustainability assessment system for a construction project. Firstly, a more thorough sustainability angle is required to address the materials and products that are used in the execution of projects, the management process, organization, key stakeholders including the project manager and team members, and economic concerns [33]. Secondly, the number of indicators should be minimal to ensure practical and cost-effective implementation [34]. Some researchers proposed very similar numbers of indicators close to thirty [35], explaining that a sustainability system with around thirty indicators is more practical and cost-effective for project performance. Thirdly, the life cycle issue should be considered. The indicator system is expected to emphasize the construction project life cycle (such as feasibility study, procurement, planning, construction, and turnover). Instead, the indicator system should also emphasize the facility life cycle (maintenance, operation, and demolition) [36]. Lastly, and most importantly, is the project focus. The indicators should be relevant to the project’s operations and tasks for effective management since the construction objectives need to be accomplished via project execution [37].

3. Research Methodology

The first step in the methodology of this study was to identify the key sustainability-specific project selection criteria in the construction industry. This was performed through a comprehensive literature review. The review focused on sustainability indicators in construction projects. These indicators are used as selection criteria. The second step was to assess the importance of these selection criteria (indicators). This assessment was conducted by distributing a survey among professionals in the UAE. The survey data were then analyzed using the Analytic Hierarchy Process (AHP) method. The survey was designed for pair-wise comparisons between criteria utilizing the AHP method. The survey was sent to experts in the UAE to evaluate the importance of the selection criteria based on their perceptions. Participants were asked to compare every two criteria using the ratio scale proposed by Saaty [38], as shown in

Table 1. Ratio scales of the AHP [38].

Intensity	Definition	Explanation
1	Equal importance	Two criteria contribute equally
3	Moderate importance	Experience and judgement slightly favor one criterion over another
5	Strong importance	Experience and judgement strongly favor one criterion over another
7	Very strong importance	A criterion is strongly favored and its dominance is demonstrated in practice
9	Extreme importance	The evidence favoring one criterion over another is of the highest possible order of affirmation

. Odd numbers from 1 to 9 were utilized to indicate the strength of the significance of each criterion. The survey was circulated to candidates in the UAE who have experience working in international and local companies such as developers, consultants, and project management firms with comprehensive knowledge of project selection in the construction business. The sample of the pair-wise comparison between the two criteria is shown in Figure 1. There is a requirement to measure which indicator is more significant while comparing two indicators and to determine the level of strength of that significance. This method permits the participants to concentrate on two criteria and then analyze the intensity to explain the relationship between the two criteria. For example, if the respondent feels that energy use is strongly favored compared to material use, then the respondent will choose 7 from the left side. If the respondent feels that material use is slightly favored compared to energy use, then the respondent will choose 3 from the right side.

The universe of participants includes decision makers in construction organizations who have knowledge and/or experience in project selection. The survey respondents included professionals working as developers, consultants, and project management firms. These professionals are responsible for selecting projects in their respective organizations, and thus their perception of the importance of selection criteria is valuable.

Thirty-four candidates completed the survey, which resulted in a response rate of 87%. The percentage of local companies that participated in the survey was 70.58%, and the remaining participants were from international companies. The experience levels of the contributors in the categories of more than 20 years and between 11 and 20 years of experience were 41.18% and 29.41%, respectively. The percentage of clients’ employees was about 38.32%, whereas the percentages of project management companies and consultants were 20.58% and 29.41%, respectively. The percentage of candidates with experience in projects with budgets of more than AED 500 million (UAE dirhams) was 41.18%, while the remaining contributors had experience in projects with budgets between AED 201 and AED 500 million (17.65%), between AED 50 and AED 200 million (23.53%), and below AED 50 million (17.66%).

4. Sustainability-Specific Criteria for Project Selection

The sustainability-specific criteria were identified through a comprehensive review of the related literature and existing standards. The first step was to identify the sustainability indicators and criteria related to the construction industry. Several indicators were extracted from these standards and research articles. These indicators were categorized into the three different pillars of environmental, social, and economic, and then each pillar was divided into groups/criteria. At this stage, each indicator was assigned to a suitable and related group under the appropriate sustainability pillar: economic, social, or environmental. The first list was reviewed to combine indicators that have similar meanings and represent similar sustainable practices. After this step, the total number of indicators was reduced in the three pillars. These groups were considered as criteria with several indicators. Shortlisting the criteria was the next step of the criteria selection process. The selection process for the criteria under each pillar was based on the number of citations. The final selection of criteria considered in this study totaled 16 items. These 16 criteria were distributed as follows: 6 criteria for the environmental pillar, 5 criteria for the social pillar, and 5 criteria for the economic pillar.

Table 2. Sustainability-specific criteria.

List of the Sustainability Criteria for Construction Projects
Sr No.	Criteria	Citation	Frequency
Environmental Criteria
1	Energy Use	Yu et al. [35], Chen et al. [39], Eweje [40], Dabirian et al. [41], Dobrovolskienė and Tamosiunienė [1], Siew [42], Huang et al. [32], Khalili et al. [8], Gerner [43], Shultz and Peterson [44], Fernandez-Sanchez and Rodriguez-Lopez [45], Pan et al. [46], Vatalis et al. [47], Shen et al. [48], CEEQUAL [49], Green Globes [50], BREEAM [51], Global Reporting Initiative (GRI) [52], EDGE [53], LEED [54], BOMA [55], Ecodistricts [56]	22
2	Material Use	Dabirian et al. [41], Siew [42], Khalili et al. [8], Yu et al. [57], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Azapagic [58], Heravi et al. [18], Pan et al. [46], Rickels et al. [59], Shen et al. [48], GreenRoads [60], Green Globes [50], Ecodistricts [56], Global Reporting Initiative (GRI) [52], LEED [54]	16
3	Water Use	Dabirian et al. [41], Dobrovolskienė and Tamosiunienė [1], Siew [42], Huang et al. [32], Fernandez-Sanchez and Rodriguez-Lopez [45], Azapagic [58], Pan et al. [46], Razmjoo et al. [61], Rickels et al. [59], Vatalis et al. [47], Shen et al. [48], CEEQUAL [49], GreenRoads [60], Green Globes [50], BREEAM [51], BOMA [55], Ecodistricts [56], Global Reporting Initiative (GRI) [52], ISO [62], LEED [54]	20
4	Land Use and Biodiversity	Chen et al. [39], Eweje [40], Martin and Assenov [63], Huang et al. [32], Khalili et al. [8], Yu et al. [57], Gerner [43], Shultz and Peterson [44], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Azapagic [58], Pan et al. [46], Karji et al. [20], Razmjoo et al. [61], Shen et al. [48], CEEQUAL [49], Green Globes [50], EDGE [53], BREEAM [51], Star Communities [64], ISO [62], Global Reporting Initiative (GRI) [52]	22
5	Pollution	Chen et al. [39], Dabirian et al. [41], Huang et al. [32], Yu et al. [57], Gerner [43], Shen et al. [25], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Azapagic [58], Heravi et al. [18], Pan et al. [46], Karji et al. [20], Shen et al. [48], GreenRoads [60], WELL [65], ISO [62], Green Globes [50], BREEAM [51]	18
6	Waste Management	Dabirian et al. [41], Siew [42], Huang et al. [32], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Rickels et al. [59], Vatalis et al. [47], Shen et al. [48], CEEQUAL [49], GreenRoads [60], WELL [65], LEED [54], BREEAM [51], BOMA [55], Ecodistricts [56], Star Communities [64], Global Reporting Initiative (GRI) [52],	17
Social Criteria
7	Public Health and Safety	Chen et al. [39], Martin and Assenov [63], Dobrovolskienė and Tamosiunienė [1], Siew [42], Huang et al. [32], Khalili et al. [8], Yu et al. [57], Gerner [43], Shultz and Peterson [44], Shen et al. [25], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Azapagic [58], Pan et al. [46], Vatalis et al. [47], Shen et al. [48], GreenRoads [60], WELL [65], BOMA [55], CEEQUAL [49], Ecodistricts [56], Star Communities [64], Global Reporting Initiative (GRI) [52], ISO [62]	24
8	Employee Training, Education, and Skill Development	Chen et al. [39], Dobrovolskienė and Tamosiunienė [1], Siew [42], Huang et al. [32], Khalili et al. [8], Shultz and Peterson [44], Azapagic [58], Karji et al. [20], Shen et al. [48], GreenRoads [60], WELL [65], BOMA [55], STAR Community [64], Global Reporting Initiative (GRI) [52]	14
9	Relationship with Local Community	R.-H. Chen et al. [39], A. Karji et al. [20], K. I. Vatalis et al. [47], Green roads [60], BOMA [55], Star Communities [64], Global Reporting Initiative (GRI) [52], IUCN Green Standard [66]	8
10	Improvement in Infrastructure	Chen et al. [39], Huang et al. [32], Yu et al. [57], Heravi et al. [18], Shen et al. [48], Green Roads [60], Ecodistricts [56], STAR Community [64], IUCN Green Standard [66]	9
11	Encourage Alternative Modes of Transportation	Dabirian et al. [41], Siew [42], Huang et al. [32], Karji et al. [20], Vatalis et al. [47], Shen et al. [48], Green Roads [60], BREEAM [51], Ecodistricts [56], Star Communities [64], ISO [62]	11
Economic Criteria
12	Life Cycle cost	Shen et al. [25], Fernandez-Sanchez and Rodriguez-Lopez [45], Shultz and Peterson [44], Rickels et al. [59], Vatalis et al. [47], CEEQUAL [49], Green Roads [60], BREEAM [51], ISO [62], ISO 15686-5 [67]	10
13	Contribution to GDP and wealth creation	Chen et al. [39], Huang et al. [32], Khalili et al. [8], Shultz and Peterson [44], Fernandez-Sanchez and Rodriguez-Lopez [45], Azapagic [58], Razmjoo et al. [61], Shen et al. [48]	8
14	Employment Creation	Dabirian et al. [41], Khalili et al. [8], Shultz and Peterson [44], Azapagic [58], Karji et al. [20]	5
15	Innovation and Technological Advance	Huang et al. [32], Gerner [43], Heravi et al. [18], LEED [54], BREEAM [51], STAR Community [64]	6
16	Use of National Suppliers	Dabirian et al. [41], Fernandez-Sanchez and Rodriguez-Lopez [45], Vatalis et al. [47], GreenRoads [60], Star Communities [64], Global Reporting Initiative (GRI) [52]	6

shows the selected 16 criteria used in this research, along with their literature sources.

The environmental criteria group includes six different criteria: energy use, material use, water use, land use, pollution, and waste management. Some of these criteria were measured based on two indicators. These six criteria include ten different sustainability indicators to be considered as project selection criteria. The energy use criterion includes two indicators: reduction in energy use and use of renewable energy. Reduction in energy use is the indicator of reducing energy use by utilizing suitable equipment, systems, and construction methodology during the design and construction phases [41]. Energy use reduction can be measured based on energy-saving efforts achieved through sustainable practices and efficient systems [44]. The use of renewable energy can be assessed through the amount of regenerated energy produced using renewable resources. The water use criterion consists of using renewable water resources and reducing water consumption [12]. Reducing water consumption may be calculated according to water consumption reduction by promoting sustainable practices and water-saving devices through the design phase and control systems [68]. The amount of water recycled through the use of sustainable machinery and practices is measured using renewable water indicators [69]. Reducing water consumption is quantified based on saving water through efficient water recycling systems, water systems, and construction methodology [70]. The use of material criterion is divided into two measurable indicators: recycled products/materials and green materials. The use of recycled products and materials is described as utilizing recycled materials during the project operation and construction stages [69]. The use of materials that do not harm the environment and the promotion of green products are measured through the use of green materials [39]. The use of recycled materials and products is separately quantified in each material’s specific measurement unit based on the amount of recycled material generated [71].

The land use criterion includes land use and rehabilitation along with impacts on biodiversity as indicators. The avoidance of consuming undeveloped and greenfield lands through the reuse of derelict areas, refurbishment zones, and brownfields, and re-development and infill sites of existing developed areas is measured through land use and rehabilitation indicators [24,36]. The impact on biodiversity indicator is used to minimize the long-term impacts of the development on the surrounding areas and sites [72]. Land use and rehabilitation are measured based on the saved area in m² due. Moreover, the pollution criterion includes air emission indicators. Greenhouse gas (GHG) emissions have possible negative impacts on the environment and climate, which can be evaluated through emission-to-air indicators [69]. Emissions to air are measured based on reducing GHG emissions from construction project activities, equipment, and machinery [73]. The waste management criterion quantifies the total amount of hazardous and non-hazardous wastes that might cause a possible negative impact on the environment through the disposal of waste materials [68]. Construction waste management is measured based on reduced construction waste related to off-site manufacture or fabrication and site construction [74].

The social criteria group includes five different criteria: public health and safety, employee training and education, relationship with the local community, improvement in infrastructure, and encouraging alternative modes of transportation. These five different social criteria are considered in the portfolio selection process. These criteria are measured differently, where health and safety criteria are evaluated by protecting consumers, employees, and the community’s health and safety [16]. Public health and safety are also measured based on reducing injuries and fatalities, reducing heavy work, and impacting physical working conditions. The training of local employees and the hiring of national businesses, which is defined as contributing to educational accomplishment and opportunity, cohesion and community, and social and cultural enrichment, are highlighted as employee training and education criteria [39]. Workers’ training and education are measured based on total training hours for project members in sustainability and are based on the percentage of improvement in the community’s educational and cultural status [75]. Relationship with the local community is a criterion that addresses caring for the environment around the development, the related population, and the local community [76]. Moreover, the relationship with the local community criterion is measured based on the relationship with local communities and wealth distribution [42]. Construction and new developments might improve a community’s current infrastructure, which is measured by the improvement in infrastructure criterion [34]. The improvement in infrastructure criterion is evaluated based on a percentage of infrastructure improvement compared with the existing situation [25]. Encouraging alternative modes of transportation is considered a criterion to explain transportation’s total distance, including shipments, transportation of materials to consumers, and commercial trips [23]. The encourage alternative modes of transportation criterion is measured based on the total number of kilometers covered for moving materials and people [47].

The economic pillar of sustainability is evaluated based on five different criteria: life cycle cost, contribution to GDP and wealth creation, employment creation, innovation and technology, and national suppliers’ use. These five different economic criteria are considered for the portfolio selection process. The life cycle cost criterion is described as expenses toward assets and spare parts through the whole project life cycle while satisfying the performance needs and the cost of maintenance and repair of amenities and overall expenditures [43]. Life cycle cost and contribution to GDP and wealth creation are estimated in the country’s currency [26]. The contribution of the total value of services and products manufactured in a country is measured by contribution to GDP criteria [59]. In contrast, the contribution to hiring, employment, and retention of jobs are measured by the amount of employment creation [59]. Innovation and technological advance criteria are described as benefits gained from technological growth, including creation, technology, and invention [77]. The use of national suppliers’ criterion refers to the use of local suppliers who produce and supply raw materials and products close to the project location [78].

5. Assessment of the Sustainability-Specific Selection Criteria

The next step was to calculate the weight for each criterion and each category by using Excel software (Microsoft Excel 2019).

Table 3. Sustainability selection criteria weights.

Sustainability			Local Weight		Global Weight
	Environmental		0.520
		Energy Use		0.318	0.165
		Material Use		0.178	0.093
		Water Use		0.170	0.088
		Land Use		0.127	0.066
		Pollution		0.120	0.062
		Waste Management		0.088	0.046
	Social		0.214
		Health and Safety		0.426	0.091
		Employee Training and Education		0.200	0.043
		Relation with Local Community		0.117	0.025
		Improvement in Infrastructure		0.172	0.037
		Alternative Transportation		0.084	0.018
	Economic		0.266
		Life Cycle Cost		0.324	0.086
		Contribution to GDP		0.220	0.059
		Employment Creation		0.177	0.047
		Innovation and Technology		0.171	0.045
		Use of National Suppliers		0.108	0.029

shows the main selection classifications and criteria along with their local and global priorities. The local priority is the weight of the selection criteria within its group, while the global priority is the weight of the selection criteria relative to the overall selection criteria [9]. The inconsistency value was also computed from the collected data to be 0.03. To be acceptable, the inconsistency value should be less than 0.1.

The analysis shows that the environmental criteria group has higher local weight compared with the other two pillars: social and economic. The higher criteria weight and more effectiveness were assigned to the environmental group because of the criteria within this group, which are recycled material, renewable energy, and the threat of water scarcity. The most effective criterion within the social group was the health and safety of the community. Moreover, it was observed that the life cycle cost is the main concern of the client due to the related cost of maintenance and repairs after project completion.

It is important to discover the most valuable criteria within each group based on the perception of contributors. The outcomes of the survey in terms of local weight for the three pillars are shown in Table 3.

The three pillars of sustainability had local weights of 0.520, 0.214, and 0.266 for the environmental, social, and economic pillars, respectively. Energy use had the highest local weight (0.317) in the environmental pillar, while health and safety was the most weighted criterion (local weight: 0.426) in the social category. Life cycle cost was ranked as the highest criterion (local weight: 0.324) in the economic pillar.

Moreover, the comparison between the three pillars of sustainability demonstrates that the environmental criteria received greater attention than others. This is due to the recycling of material, using renewable energy, environmental impacts, and the threat of water scarcity. Moreover, it should be considered that employee and community health and safety are the most significant criteria in the social category based on the survey results. Furthermore, one of the main client concerns regarding the economic pillar is the life cycle cost due to high operation and maintenance costs after project completion and during the defined project life cycle.

6. Conclusions

The objective of this research was to identify and assess the sustainability-specific selection criteria that can be used to select construction projects in the United Arab Emirates. The results demonstrate that the selection criteria obtained from the literature review are significant to various degrees. The criteria under the environmental pillar are perceived to be more significant than the other two pillars of sustainability: social and economic. Energy use, health and safety, and life cycle cost are the most significant criteria in each of the three pillars of sustainability: environmental, social, and economic, respectively. This is due to the nature of construction projects. Energy use, material use, and water use are the most important criteria within the environmental pillar, which highlights the importance of the use of natural resources and their negative impact on the environment. Although the “alternative transportation” criterion received a lesser weight, it is still a significant factor in portfolio selection because of the promotion of different types of public transportation. The importance of health and safety in the social pillar is perceived based on the collected data. The research outcomes of this study can assist decision makers in assessing potential projects in their portfolio pool during the selection process by incorporating the sustainability value and implementing a sustainability selection process. This confirms that portfolio selection based on the most effective sustainability criteria can reduce negative environmental impacts and increase the satisfaction levels of society and communities. Moreover, these results can be generalized to the international context despite the fact that this study was developed based on the perceptions of experts in the UAE.

This research paves the way for future portfolio selection based on the sustainability value by developing sustainability selection criteria and a process that permits clients to compare various projects and programs within a portfolio pool against sustainability selection criteria in the construction industry. A two-step selection process can be proposed, where projects are pre-selected based on their ability to comply with sustainability standards and meet client satisfaction criteria from an environmental point of view; then, the selected projects can be further evaluated based on the selection criteria of the social and economic pillars. Future research may study the relationship between these identified criteria and the performance of sustainable construction.