Sustainability Performance in On-Site Construction Processes: A Systematic Literature Review

: One of the most important challenges in the construction industry is to develop projects covering all three dimensions of sustainability: economic, social, and environmental. However, the construction project management literature lacks clarity regarding the fundamental principles and effective strategies for implementing sustainability for on-site construction processes. This article provides a comprehensive analysis of the sustainability dimensions in the construction sector, highlighting sustainability key performance indicators (KPIs) for on-site practices. The analysis stems from a systematic literature review sourced from the Web of Science and Scopus databases. The search identified 17 environmental, 20 social, and 15 economic indicators, with the most relevant being those associated with key terms such as cost, profit, labor, customer satisfaction, community impact, resource utilization, and contaminant management. The theoretical implications of this study contribute a critical framework for integrating the sustainability dimensions into construction practices, advancing the industry’s sustainability. For practitioners, the findings offer a prioritized guide to enhance on-site construction processes (O-SCP) sustainability and provide measurable KPIs for tracking progress toward sustainable development goals. This study not only sheds light on the current application of sustainability in O-SCP but also paves the way for future research to further this field.


Introduction
The construction industry has historically faced challenges in integrating sustainable practices throughout its lifecycle and on-site operations [1].Sustainable processes, such as those aimed at reducing energy or water consumption, are essential for creating an enduring built environment that adheres to the 'triple bottom line' concept of sustainability [2].Typically, On-Site Construction (O-SC) involves intricate and fragmented processes that can lead to adverse outcomes [3], including project delays, material waste, and inefficiency in production, which in turn pose significant risks to the natural environment [4].Addressing these issues necessitates a detailed examination of the sustainability efforts in on-site construction to comprehend the intertwined environmental, social, and economic dimensions [5,6].This article undertakes a Systematic Literature Review (SLR) to map the field of sustainability Key Performance Indicators (KPIs) for O-SC practices, identifying gaps and establishing new research directions [5].
The concept of sustainability was initially proposed in the 1980s by the World Commission on Environment and Development (WCED), culminating in a seminal report to the United Nations General Assembly.The Commission's 1987 Brundtland Report famously characterized sustainable development as the ability to satisfy current needs without compromising the future generations' ability to meet their own [7,8].Subsequently, in the early 1990s, the three critical dimensions of sustainability-economic, social, and environmental-were formally recognized, providing a comprehensive model for sustainable progress [9].
Scholarly attention to sustainable development has surged following the initiation of the '2030 Agenda for Sustainable Development' in 2015 [10].Based on that, the environmental impacts of On-Site Construction Processes (O-SCP) have been proven and accepted [8].Researchers have shown that the construction industry affects the environment in numerous ways across projects' life cycles [9]; generating significant negative environmental impacts [11].Particularly from the perspective of O-SCP, there is an increasing demand for environmentally friendly practices to minimize the negative impacts associated with the building sector [12].
Numerous research studies have explored various practices linked to Sustainable Construction (SC) from different angles [13].Some standout studies in this field have played a significant role in highlighting crucial aspects and finding ways to reduce the negative impacts associated with construction processes [14].For instance, [15] conducted a comprehensive literature review on SC, searching into its definition, assessment approaches, and the barriers and drivers shaping its implementation.Similarly, [16] investigated sustainable infrastructure, emphasizing material-sharing strategies and utilizing Life Cycle Assessment (LCA) to attain sustainability.Additionally, [17] concentrated on green building promotion, identifying key success factors from pertinent studies.However, these studies, while exploring sustainability in infrastructure and buildings, do not extensively cover sustainability in processes related to construction [18].
Ref. [19] provided insights into integrating sustainability KPIs into construction processes through empirical studies, providing critical perspectives on sustainability, particularly within social performance.Additionally, [20] contributed to the literature by mapping trends in building sustainability assessment, addressing research progress, international implications, and associated development trends within SC.Ref. [21] systematically analyzed the scientific evolution of sustainable buildings assessment using LEED and BREEAM, while [22] discussed strategies for durability, affordability, and resource conservation to enhance SC, focusing on the sustainability implications of buildings' service life.Moreover, [23] introduced a multi-dimensional assessment standard for SC processes' performance, presenting a comprehensive evaluation framework.Despite these significant contributions, existing review articles often focus on specific topics, lacking comprehensive studies that incorporate sustainability KPIs across construction processes [24].
This article responds to such exigencies by evaluating and synthesizing a range of scholarly contributions within the field of construction management to understand sustainability KPIs across construction processes comprehensively.
Therefore, this article addresses the following research questions: (i) How many sustainability KPIs in O-SCP can be identified from published literature?(ii) What are the different categories of sustainability KPIs implemented in O-SCP?
The structure of the article is organized as follows: Section 2 delineates the research methodology.Section 3 presents the results of the bibliometric analysis, covering literature from 2002 to 2022, outlining the research themes and trends to obtain sustainability KPIs.Section 4 engages in further discussion on the findings and methodologies, setting the stage for future research inquiries.Section 5 highlight limitations, and Section 6 provides the concluding remarks of the study.

Research Method
To address the research questions, an SLR was conducted within the Scopus and Web of Science databases, which are widely recognized as extensive repositories of peerreviewed scholarly manuscripts [17].The methodology for the SLR entailed five distinct phases: (i) selection of keywords; (ii) execution of a comprehensive search; (iii) review of articles; (iv) qualitative analysis; and (v) quantitative analysis.These phases are illustrated in Figure 1, detailing the SLR process.Additionally, the PRISMA 2020 Statement (Supplementary Materials) was employed in the SLR to guide the selection criteria for including or excluding articles.This approach ensured comprehensive reporting, increased confidence in the overall findings, and decreased duplication of articles, as depicted in Figure 2.
Sustainability 2024, 16, x FOR PEER REVIEW 3 of 22 in Figure 1, detailing the SLR process.Additionally, the PRISMA 2020 Statement (Supplementary Materials) was employed in the SLR to guide the selection criteria for including or excluding articles.This approach ensured comprehensive reporting, increased confidence in the overall findings, and decreased duplication of articles, as depicted in Figure 2.

Phase I: Initial Keywords Selection
The initial phase of the research involved comprehensive searches across the databases to gather a significant collection of relevant academic articles.The research started by searching various databases to gather a lot of relevant academic articles.This phase was crucial as it focused on two main things: finding previous articles to understand similar work done before and creating specific search terms [25].To begin, they used broad criteria like subject areas, titles, authors, and keywords to find around 200 articles on sustainability performance in construction.This helped prevent repeating existing work and understand what had already been studied related to the chosen topics.It was important in Figure 1, detailing the SLR process.Additionally, the PRISMA 2020 Statement (Supplementary Materials) was employed in the SLR to guide the selection criteria for including or excluding articles.This approach ensured comprehensive reporting, increased confidence in the overall findings, and decreased duplication of articles, as depicted in Figure 2.

Phase I: Initial Keywords Selection
The initial phase of the research involved comprehensive searches across the databases to gather a significant collection of relevant academic articles.The research started by searching various databases to gather a lot of relevant academic articles.This phase was crucial as it focused on two main things: finding previous articles to understand similar work done before and creating specific search terms [25].To begin, they used broad criteria like subject areas, titles, authors, and keywords to find around 200 articles on sustainability performance in construction.This helped prevent repeating existing work and understand what had already been studied related to the chosen topics.It was important

Phase I: Initial Keywords Selection
The initial phase of the research involved comprehensive searches across the databases to gather a significant collection of relevant academic articles.The research started by searching various databases to gather a lot of relevant academic articles.This phase was crucial as it focused on two main things: finding previous articles to understand similar work done before and creating specific search terms [25].To begin, they used broad criteria like subject areas, titles, authors, and keywords to find around 200 articles on sustainability performance in construction.This helped prevent repeating existing work and understand what had already been studied related to the chosen topics.It was important to learn about different methods used, find gaps in knowledge, and shape the research questions for the SLR [26].The second step pinpointed important keywords like 'Sustainability Performance', 'Sustainability in Construction', 'Sustainable Construction', and others in the articles to refine the search strategy.

Phase II: Comprehensive Search
This search started without any limitations on publication dates, publishers, document types, or categories.The PRISMA 2020 Statement flow diagram and checklist was used to carefully choose and examine through relevant articles filtering pertinent content related to sustainability KPIs in construction, as depicted in Figure 2 [25].Searches were executed using Boolean operators created in Phase I, in the following manner: TITLE-ABS-KEY ('Sustainability Performance' OR 'Sustainability in Construction' OR 'Sustainable Construction') AND TITLE-ABS-KEY ('Sustainability Indicators' OR 'Sustainability Assessment' OR 'Sustainability Metrics').This structured approach helped to identify an extensive collection of literature pertinent to the study's aims.The criterion to determine the necessary article quantity was based on the frequency of occurrence in the search results; an article appearing multiple times signaled a point to either cease the search or modify the Boolean string.This approach yielded an initial list of 11,083 publications, which were then advanced to the third phase for an in-depth bibliometric analysis and review.

Phase III: Article Review
This phase targeted publications from 2002 to 2022 and initially excluded 359 articles.The next step involved a rigorous categorization process, which further refined the selection by excluding 7076 documents that did not qualify as articles or review articles.Of the 354 articles that remained, a detailed topic and category evaluation was conducted, resulting in the removal of studies not specifically focused on the interplay between sustainable practices, sustainability KPIs, and on-site construction processes.This focused the review on articles relevant to sustainability performance in construction processes, narrowing the field to 219 articles.Further screening based on publication titles and publishers led to the exclusion of an additional 11 articles.Once duplicates were removed, 101 unique articles were left, which were then taken forward for qualitative analysis in Phase IV.

Phase IV: Qualitative Process
A thematic synthesis procedure was applied to the remaining 101 articles.The abstracts of these articles were examined, leading to the exclusion of those not pertinent to construction projects, O-SCP, or sustainability and its KPIs within the construction context.A detailed analysis of the full texts was necessary to discern relevant sustainability KPIs, a process that entailed extracting specific sustainability measures from each article [26].The selection process identified 40 articles for the Systematic Literature Review (SLR), as listed in Table 1.These articles specifically focus on measuring key performance indicators (KPIs) in the construction field and explore how sustainability relates to construction.They thoroughly cover sustainability measures and how they connect with sustainable practices in construction [27].

Phase V: Quantitative Process
This phase involved a quantitative analysis to synthesize the body of research on sustainable building projects.Microsoft Excel and the Web of Science (WOS) platform, known for its extensive bibliometric capabilities, were utilized to facilitate this analysis.Using the features available on WOS, the study examined the 40 selected articles, extracting quantitative data that shed light on themes, keywords, citation counts, references, and authorship patterns within the sustainable building projects literature.This structured, three-step quantitative method is elaborated in Figure 3.
The initial step of the quantitative analysis entailed a thorough review of the articles selected, assessing elements such as publication date, source, geographical distribution, and citation count from 2002 to 2022.This process delineated the evolution of construction management trends, spotlighted leading journals, and gauged regional influences, while also emphasizing the most frequently cited works [28,29].A co-citation analysis was conducted using Excel spreadsheets in conjunction with WOS citation analysis.This analysis aimed to enhance the comprehension of systematic review findings derived from the 40 articles.It helped create a more vivid and comprehensive depiction of the research network and the interconnected themes, providing a clearer visual and conceptual under-standing [29].In the second step, the co-citation analysis was expanded to identify research clusters and key themes, employing citation frequency of the sustainability KPIs to group the articles and evaluate their significance and influence.The identification of these themes was instrumental in identifying sustainable aspects and clustering the sustainability KPIs.
management trends, spotlighted leading journals, and gauged regional influences, while also emphasizing the most frequently cited works [28,29].A co-citation analysis was conducted using Excel spreadsheets in conjunction with WOS citation analysis.This analysis aimed to enhance the comprehension of systematic review findings derived from the 40 articles.It helped create a more vivid and comprehensive depiction of the research network and the interconnected themes, providing a clearer visual and conceptual understanding [29].In the second step, the co-citation analysis was expanded to identify research clusters and key themes, employing citation frequency of the sustainability KPIs to group the articles and evaluate their significance and influence.The identification of these themes was instrumental in identifying sustainable aspects and clustering the sustainability KPIs.In the final step, the SLR focused on developing four concept maps to aid in the data analysis and interpretation, prioritizing sustainable aspects and sustainability KPIs based on the citation frequencies [28].The first three maps were informed by insights gained from the earlier phases, while the fourth featured a code comparison to analyze the nexus between construction practices and sustainability principles.These concept maps synthesized findings from both quantitative and qualitative analyses, ensuring that the identified sustainability KPIs were deeply anchored in the empirical data and clearly reflected the core facets of the research question.This integrative approach facilitated the delineation of the three fundamental sustainability dimensions in building construction and the classification of pivotal KPIs prevalent in standard construction methodologies based on citation frequencies.

Findings
The findings of this article were segmented into two sections [26].The first section presents an exploratory data analysis, while the second provides an in-depth document analysis of the articles selected for this literature review, and their source of publication as organized in Tables 1 and 2. These tables categorize the articles by citation count, starting with the most cited publication.Furthermore, this section introduces three principal research themes that frame the discussion of sustainability KPIs, which are closely associated with traditional construction practices as identified in the literature: (i) Construction Processes, (ii) Key Performance Indicators (KPIs) or Sustainable dimensions, and (iii) Sustainable Construction.These principal research themes are presented in Table 3.In the final step, the SLR focused on developing four concept maps to aid in the data analysis and interpretation, prioritizing sustainable aspects and sustainability KPIs based on the citation frequencies [28].The first three maps were informed by insights gained from the earlier phases, while the fourth featured a code comparison to analyze the nexus between construction practices and sustainability principles.These concept maps synthesized findings from both quantitative and qualitative analyses, ensuring that the identified sustainability KPIs were deeply anchored in the empirical data and clearly reflected the core facets of the research question.This integrative approach facilitated the delineation of the three fundamental sustainability dimensions in building construction and the classification of pivotal KPIs prevalent in standard construction methodologies based on citation frequencies.

Findings
The findings of this article were segmented into two sections [26].The first section presents an exploratory data analysis, while the second provides an in-depth document analysis of the articles selected for this literature review, and their source of publication as organized in Tables 1 and 2. These tables categorize the articles by citation count, starting with the most cited publication.Furthermore, this section introduces three principal research themes that frame the discussion of sustainability KPIs, which are closely associated with traditional construction practices as identified in the literature: (i) Construction Processes, (ii) Key Performance Indicators (KPIs) or Sustainable dimensions, and (iii) Sustainable Construction.These principal research themes are presented in Table 3.

Exploratory Data Analysis
This assessment was aimed at analyzing the annual distribution of publications; the distribution across journals, citations, and publication years is shown in Figure 4.An important escalation in article publication has been observed since 2019, suggesting an intensifying scholarly focus on sustainability within the construction sector [30].This trend is expected to continue, especially considering that this literature review only encompasses articles published until February 2022, implying that the count for that year is likely higher.
Building and Environment, a leading journal ranked 'Q1' in the Scimago Journal & Country Rank (SJR), was the most prolific, contributing eight articles as noted in Table 2.Additional prominent sources were the 'Journal of Construction Engineering and Management' and 'Sustainable Cities and Society', both of which hold 'Q1' rankings in SJR, signifying their relevance as academic journals.Furthermore, a geographical analysis unveiled in Figure 5 indicates that researchers from China and the United States lead with eight publications each.They are followed by Canada and India with three and two publications, respectively, and Chile and Taiwan, contributing two each.

Exploratory Data Analysis
This assessment was aimed at analyzing the annual distribution of publications; the distribution across journals, citations, and publication years is shown in Figure 4.An important escalation in article publication has been observed since 2019, suggesting an intensifying scholarly focus on sustainability within the construction sector [30].This trend is expected to continue, especially considering that this literature review only encompasses articles published until February 2022, implying that the count for that year is likely higher.Building and Environment, a leading journal ranked 'Q1' in the Scimago Journal & Country Rank (SJR), was the most prolific, contributing eight articles as noted in Table 2.Additional prominent sources were the 'Journal of Construction Engineering and Management' and 'Sustainable Cities and Society', both of which hold 'Q1' rankings in SJR, signifying their relevance as academic journals.Furthermore, a geographical analysis unveiled in Figure 5 indicates that researchers from China and the United States lead with eight publications each.They are followed by Canada and India with three and two publications, respectively, and Chile and Taiwan, contributing two each.

Document Analysis
This stage highlights the integration of sustainability in construction, focusing on the balance among economic, social, and environmental dimensions [31].Additionally, it examines KPIs for O-SCP [32,33].Table 3 shows how different articles are connected based on research themes like construction methods and sustainable construction.The symbol ʹxʹ represents that the specific research stream was found in the article.It includes the selected 40 articles to examine how sustainability and construction are linked, focusing on sustainability KPIs and O-SCP [34].Table 4 details the specific sustainable aspects addressed in the 40 articles to define sustainability KPIs.Additionally, Table 4 categorizes these articles thematically, highlighting a predominant focus on the three dimensions of sustainability: environmental, social, and economic.These articles helped to evaluate the sustainability of construction projects by combining sustainability KPIs with sustainable aspects [35].

Document Analysis
This stage highlights the integration of sustainability in construction, focusing on the balance among economic, social, and environmental dimensions [31].Additionally, it examines KPIs for O-SCP [32,33].Table 3 shows how different articles are connected based on research themes like construction methods and sustainable construction.The symbol 'x' represents that the specific research stream was found in the article.It includes the selected 40 articles to examine how sustainability and construction are linked, focusing on sustainability KPIs and O-SCP [34].Table 4 details the specific sustainable aspects addressed in the 40 articles to define sustainability KPIs.Additionally, Table 4 categorizes these articles thematically, highlighting a predominant focus on the three dimensions of sustainability: environmental, social, and economic.These articles helped to evaluate the sustainability of construction projects by combining sustainability KPIs with sustainable aspects [35].

Sustainable Buildings
Built Environment x x A40 * * Within the context of key performance indicators, it is important to note that certain articles are categorized as general information.This classification occurs when these articles do not align with any specific indicator categories.
The analysis reflects an increased focus on the interaction between sustainability concepts and construction performance, particularly from 2019 onwards.This period accounts for half of the published articles (20 out of 40) in this domain, highlighting a surge in research interest during these years.Such a trend suggests that the examination of sustainability performance within O-SCP is a developing area of scholarly inquiry [36].
Accordingly, the selection of 40 articles aimed to facilitate an in-depth reading of each article, allowing for a thorough identification of the pertinent sustainability KPIs highlighted in Tables 3 and 4 through a comprehensive examination.Furthermore, Tables 3 and 4 catalog the sources of each word represented on the concept maps.These maps were constructed based on insights derived from the 40 articles, delineating the primary themes and their associations within each sustainability domain.Figures 6-8 visually present concept maps illustrating the interconnections among Key Performance Indicators (KPIs), while Tables 5 and 6 outline their corresponding citation frequencies.Figure 6 synthesizes the principal environmental aspects related to on-site construction projects as identified in the reviewed articles and its citation frequencies using a dataset of 149 citations to examine the principal aspects related to sustainability KPIs.'Resource Utilization' is the most cited category at 11%, and 'Water' has a 7% citation frequency, indicative of its critical role in construction.'Chemicals' and 'Contaminants' also hold significant shares with 7% and 9%, respectively.Within these categories, 'Materials' command a 6% citation frequency, with 'Packaging Materials' being the most cited subcategory at 3%.'Energy' has a total citation frequency of 5%, segmented into smaller proportions for 'Fuel', 'Natural Gas', and 'Electricity', each at 1%. 'Pollution' is another notable category at 6%, encompassing 'Acoustic' and 'Electro-magnetic' pollution.The presence of 'Air Emissions' at 7%, 'CO 2 ' at 3%, and other pollutants in soils underscores the environmental impact of construction activities [37][38][39].presence of 'Air Emissions' at 7%, 'CO2' at 3%, and other pollutants in soils underscores the environmental impact of construction activities [37][38][39].Finally, Figure 9 classifies the scope of the SLR, focusing on the interrelation between 'Sustainability' and 'Construction'.The three spheres represent the main thematic areas of the reviewed literature.The overlapping areas of the circles indicate the interdisciplinary nature of the literature, with some articles addressing multiple themes that intersect at various points.This map serves as a visual guide to understanding how the reviewed articles, denoted by codes referenced in Table 1, contribute to and are categorized within Finally, Figure 9 classifies the scope of the SLR, focusing on the interrelation between 'Sustainability' and 'Construction'.The three spheres represent the main thematic areas of the reviewed literature.The overlapping areas of the circles indicate the interdisciplinary nature of the literature, with some articles addressing multiple themes that intersect at various points.This map serves as a visual guide to understanding how the reviewed articles, denoted by codes referenced in Table 1, contribute to and are categorized within the broader research context of sustainability as it applies specifically to the construction industry.1).

General Perspectives
Table 3 presents a significant intersection of research streams within the domains of sustainability and construction, signaling a growing acknowledgment of sustainable practices' importance within construction organizations and across project lifecycles [40].For example, ref. [32] concluded that the implementation of KPIs is crucial for advancing sustainability in SC, as KPIs establish a quantifiable framework for evaluating sustainability achievements at organizational and project levels.Moreover, it is relevant to highlight that ref. [41] underscored the alignment of sustainable practices in construction with the elimination of processes that do not add value and may adversely affect the environment.Conversely, ref. [31] suggested that sustainable practices should originate from stakeholders' early decisions [42].
The literature review also reveals two important issues concerning stakeholder engagement in sustainable construction.The first issue, identified by ref. [22], is the lack of support from key stakeholders in construction projects that aim to adopt sustainable practices.The second issue, noted by ref. [33], is the gradual pace at which sustainability awareness is rising among stakeholders within construction projects.To address these concerns, ref. [21] suggested that the endorsement of sustainable practices among construction stakeholders could be effectively achieved through the creation of frameworks and rating systems anchored in KPIs [43][44][45].Collectively, the findings underscore the pivotal role stakeholders play, along with the necessity for developing robust frameworks, KPIs, and rating systems to diminish the environmental footprint of construction activities [34].

Sustainability Dimensions and KPIs
Enhancing the sustainability performance of O-SCP is crucial for efficient resource use.Ref. [33] provided an analysis of environmental impact mitigation, cost reduction, and improvement of social standards within impacted communities.In contrast, ref. [35] highlighted that the implementation of sustainability-enhancing methodologies is often challenging due to the inherent complexities and uncertainties of O-SCP.
Accordingly, the significant consumption of natural resources by construction pro-  1).

General Perspectives
Table 3 presents a significant intersection of research streams within the domains of sustainability and construction, signaling a growing acknowledgment of sustainable practices' importance within construction organizations and across project lifecycles [40].For example, ref. [32] concluded that the implementation of KPIs is crucial for advancing sustainability in SC, as KPIs establish a quantifiable framework for evaluating sustainability achievements at organizational and project levels.Moreover, it is relevant to highlight that ref. [41] underscored the alignment of sustainable practices in construction with the elimination of processes that do not add value and may adversely affect the environment.Conversely, ref. [31] suggested that sustainable practices should originate from stakeholders' early decisions [42].
The literature review also reveals two important issues concerning stakeholder engagement in sustainable construction.The first issue, identified by ref. [22], is the lack of support from key stakeholders in construction projects that aim to adopt sustainable practices.The second issue, noted by ref. [33], is the gradual pace at which sustainability awareness is rising among stakeholders within construction projects.To address these concerns, ref. [21] suggested that the endorsement of sustainable practices among construction stakeholders could be effectively achieved through the creation of frameworks and rating systems anchored in KPIs [43][44][45].Collectively, the findings underscore the pivotal role stakeholders play, along with the necessity for developing robust frameworks, KPIs, and rating systems to diminish the environmental footprint of construction activities [34].

Sustainability Dimensions and KPIs
Enhancing the sustainability performance of O-SCP is crucial for efficient resource use.Ref. [33] provided an analysis of environmental impact mitigation, cost reduction, and improvement of social standards within impacted communities.In contrast, ref. [35] highlighted that the implementation of sustainability-enhancing methodologies is often challenging due to the inherent complexities and uncertainties of O-SCP.
Accordingly, the significant consumption of natural resources by construction projects necessitates the delineation of associations between sustainability dimensions and their respective KPIs for O-SCP [36], as depicted in Tables 7-9.Although some researchers indicated the absence of universally recognized comprehensive KPI frameworks for evaluating these processes [25] the KPIs selected for this review were identified from the 40 articles selected through a full text focusing on sustainable rating systems and frameworks related to construction, buildings, or infrastructure.This review process underscores the value of KPIs in examining sustainability performance in O-SCP, reflecting their broad beneficial impacts [46].Based on the conducted review, a strategic selection of sustainable KPIs can align construction practices more closely with global sustainability goals and frameworks [31].Systems focused on O-SCP, as concluded by [47], offer numerous benefits, such as pollution control and optimized resource allocation [48,49].These systems also foster improved compliance with regulations, risk assessment, and proactive problem prevention [26].The impact of sustainable KPIs on cost-effectiveness, as revealed by [28], accentuates their role in long-term financial sustainability within the construction industry.However, gaps in the measurement and standardization of sustainable KPIs remain, as noted by [50,51].
To assess the environmental aspect of sustainability in O-SCP, a range of KPIs can be utilized to compute sustainability scores [29,52].As shown in Table 7, it is possible to list the environmental factors along with corresponding KPIs, encompassing the consumption of materials, water, energy, and chemical products during construction activities [30,53].This list also includes air pollution and emissions, highlighting the effects of CO 2 production and noise pollution, among others [31,54].Notably, the past decade of construction literature has focused on reducing material waste and conserving resources [32,55].
In terms of quantifying the social dimension of sustainability in O-SCP, the literature acknowledges that this is more complex than establishing environmental KPIs [56,57].As outlined in Table 8, the social dimension encompasses three primary areas: labor, customers, and community [22,33].These areas cover labor rights, working conditions, community engagement in labor, and the satisfaction of customers and the broader society [34,35].Satisfaction and wellbeing metrics are essential as they reflect the project's ability to engage with stakeholders and the local community, which is crucial for O-SCP success [3,58].
Training is highlighted as a pivotal factor; studies suggest that sustainability-focused training can enhance O-SCP and help achieve project objectives [36,59].However, research on the social performance of projects and their impacts is currently sparse [60][61][62].
The interplay between the social and environmental aspects in O-SCP not only addresses environmental impacts but can also enhance profitability [8].This connection underscores the interdependence of the social and environmental facets with the economic outcomes of construction projects [27,63].This connection highlights the interdependence of the social and environmental considerations with the economic outcomes of construction projects [64].As shown in Table 9, economic sustainability in O-SCP includes on-site engineering measures and activities related to technical feasibility and viability [65][66][67].It is thus posited that economic viability in O-SCP encompasses resource optimization leading to either cost savings or revenue increases [30,68], which clearly translate into sustained productivity gains in the long-term [8].

Sustainability Assessment and Implementation
The surveyed literature indicates the preponderance of various frameworks, (e.g., guidelines and green rating systems) like LEED, BREEAM, and CASBEE, which are instrumental in evaluating sustainability in O-SCP [32,39].Studies [69,70] provided a structured approach for project teams and stakeholders to attain sustainability objectives, recommending tools to organize information critical to O-SCP and delineating methods to integrate sustainability into construction projects [36].The literature notes that applying these frameworks in worker training or site inductions can substantially increase awareness of sustainable practices [42].
In this context, numerous tools have been developed to assess and quantify sustainability in projects [69].These tools typically use a set of criteria within a framework and apply a scoring system to evaluate various sustainability factors [47].It has been highlighted that these factors may be linked to resource usage minimization [71], renewable and recyclable resource maximization, natural environment conservation, and the creation of a healthy, non-toxic environment [72].As shown in Figures 6-8, sustainability management frameworks and tools can be integrated with on-site activities through KPIs aimed at specific O-SCP outcomes [11,18].This integration is essential for assessing sustainability performance within construction projects [31,73].As depicted in Figure 9.In this sense, proper adoption of the identified KPIs can lessen the economic, social, and environmental impacts associated with construction activities, tackling inefficiencies in a sector faced with notable sustainability hurdles [16,44].
Overall, the adoption of sustainability frameworks and their corresponding tools carries significant theoretical and practical implications [74].Theoretically, they enhance the sustainability discourse by providing a systematic way to conceptualize and assess the sustainability of construction projects [75].These frameworks offer a lens to critically examine and enhance the construction industry's practices [76].The identification and application of KPIs within these frameworks facilitate empirical sustainability research, laying the groundwork for scholarly investigation into sustainable construction methods [77].This re-search is imperative for understanding how sustainability can be consistently implemented and measured in O-SCP [78].
In practical terms, these sustainability assessment tools present a standardized approach for documenting and tracking sustainability performance [8,79].Implementing standards like LEED, BREEAM, and CASBEE empowers project teams to measure and improve sustainability performance, leading to efficient resource use, cost savings, and socially beneficial construction practices [35].Embedding these standards in worker training and site inductions is crucial, as it ingrains sustainability principles into everyday project operations, cultivating a pervasive culture of sustainability [50].
Given these implications, it is evident that sustainability frameworks and tools are not merely for meeting compliance but should be harnessed as strategic resources [80].They should be fully incorporated into the entire project lifecycle, making sustainability an integral part of every construction project [57].

Future Research Directions
The literature critically highlights that the theoretical advantages of sustainability frameworks and KPIs often clash with the reality of their application within the construction industry [68].The challenge lies not only in stakeholder engagement and the harmonization of sustainability goals with existing practices but also in the inherent resistance to operational change [31].These factors cumulatively create significant barriers to the practical implementation of sustainability measures [73].
Future research must delve into the effectiveness of these frameworks and KPIs, assessing their flexibility and impact across varied project scales and stakeholder interests [74].The goal is to understand the adaptability of sustainability tools in real-world settings, considering the diversity of construction environments and the unique demands of different project types [40,81].This understanding is crucial for refining the tools to be more inclusive and responsive to the specific challenges faced by the industry [82,83].
Investigations into the scalability of sustainability initiatives will further ensure that these practices are not merely theoretical ideals but actionable strategies integrated throughout the construction process [40,55].By mapping out the impediments to the adoption of sustainability measures, researchers can develop more robust frameworks that are both adaptive to the needs of the construction sector and effective in overcoming the sector's reluctance to change [84].This approach should yield pragmatic insights that can streamline the adoption of sustainability practices, ultimately leading to their seamless integration into the construction sector and contributing to a more sustainable future [24,85,86].

Limitations
Despite achieving the study objectives, this systematic literature review acknowledges certain limitations.Primarily, the review's focus on journal articles meant the exclusion of other valuable sources such as conference papers, industry reports, and policy documents, potentially overlooking relevant insights.The restriction to articles from the Web of Science and Scopus databases may not represent the entirety of available literature, and thus, important contributions from other databases or grey literature may have been omitted.
Secondly, the 52 KPIs identified may not comprehensively cover all KPIs relevant to sustainability in on-site construction processes due to the exclusion of certain document types, like conference articles.Furthermore, while the selected timeframe for the articles reviewed was extensive, it may not have captured the latest emerging trends and methodologies not yet published or indexed.
Thirdly, the cluster analysis conducted in this study and the resulting categorization of aspects were intuitively derived, referencing existing classifications and introducing the potential for overlap and misallocation of KPIs into categories.Consequently, the applied clustering of aspects is somewhat subjective and should be regarded as conceptual guides rather than definitive categories.
Fourthly, the prioritization of indicators based on citation frequencies presents a potential bias, as citation count may not accurately reflect the practical significance of an indicator in specific contexts.Nevertheless, the qualitative and quantitative outcomes of the analysis offer a useful reference for benchmarking and comparing findings from empirical studies.
Fifthly, this study did not explore how KPIs might perform or vary across different organizational or cultural settings or potential differences influenced by geographical locations.This contrasts with its extensive timeframe coverage and insightful cluster analysis.
Despite these limitations, this study provides a valuable foundation for understanding the current scope of sustainability performance in construction.It also highlights areas for further research, such as the inclusion of a broader range of literature sources, updated methodologies, and a more nuanced analysis of sustainability KPIs to enrich the understanding of sustainability in the construction sector.

Conclusions
This study examined and charted specific sustainability KPIs pertinent to O-SCP.A systematic literature review (SLR) was conducted to evaluate 40 articles from 12 multidisciplinary journals spanning 2002 to 2022.Trend analysis revealed a significant increase in sustainable construction and interest in triple bottom-line indicators in O-SCP over the past 4 years.
The review has highlighted specific sustainable aspects and sustainability KPIs pertinent to O-SCP: six aspects with seventeen indicators for the environmental dimension; seven aspects with twenty indicators for the social dimension; and two aspects with fifteen indicators for the economic dimension with the top seven most-cited ones being the cost and profit of economic dimension, labor, customer, and community of social dimension; resource utilization; and contaminants of environmental dimension.
The study's outcomes hold significant implications for both theory and practice.Theoretical implications involve establishing a comprehensive set of critical aspects and indicators for O-SCP.The integration of social, environmental, and economic considerations into key O-SCP is identified as crucial for advancing sustainability within the construction industry.The study organizes these dimensions into seven aspects, providing a foundational framework for the practice of sustainability in O-SCP.
From a managerial perspective, the findings have dual implications.Firstly, by identifying and prioritizing sustainability KPIs and aspects, the study offers guidance to practitioners and project team members on enhancing sustainability in O-SCP.Secondly, the KPIs serve to assess and convey information about the environmental, social, and economic aspects of construction.
These sustainability KPIs become tools to measure and evaluate the performance of these dimensions over time, aiding in tracking progress toward sustainable development goals in O-SCP.They serve as quantifiable measures of sustainability-related factors, enabling decision-makers to monitor trends and pinpoint areas for improvement that balance the three dimensions of sustainability in construction.Previously, the application of sustainability in O-SCP was not clearly defined.This review has uncovered several avenues for further research, providing an avenue for scholars to broaden and deepen the knowledge on enhancing sustainable performance in construction projects.

Figure 6 .
Figure 6.Environmental aspects of on-site construction processes.

Figure 7
Figure 7 depicts the principal social aspects connected with on-site construction projects, based on 115 citations to examine the principal aspects related to sustainability KPIs in this dimension.The categories 'Labor', 'Community', and 'Customer Satisfaction' are the focal points, with 'Labor' accounting for 13% of citations and 'Community' for 10%.Indicators like 'Fair Salary', 'Equal Opportunity', 'Association', 'Working Hours', 'Work Load', 'Air Quality', 'Acoustic Comfort', 'Training and Development', and 'Complaints' each make up 3%, indicating a diverse range of social considerations in construction.Indicators cited at 2%-'Thermal Comfort', 'Occupational Health and Safety', 'Health Insurance', 'Reward', 'Labor Satisfaction', 'Turnover', 'Absenteeism', 'Efforts Against Corruption', 'Health, Safety and Environmental Hazards', 'Local Employment', 'Engagement with Community', and 'Community Complaints'-highlight the industry's focus on worker well-being, retention, and the impact on society.

Figure 6 .
Figure 6.Environmental aspects of on-site construction processes.

Figure 7
Figure 7 depicts the principal social aspects connected with on-site construction projects, based on 115 citations to examine the principal aspects related to sustainability KPIs in this dimension.The categories 'Labor', 'Community', and 'Customer Satisfaction' are the focal points, with 'Labor' accounting for 13% of citations and 'Community' for 10%.Indicators like 'Fair Salary', 'Equal Opportunity', 'Association', 'Working Hours', 'Work Load', 'Air Quality', 'Acoustic Comfort', 'Training and Development', and 'Complaints'

Figure 6 .
Figure 6.Environmental aspects of on-site construction processes.

Figure 7
Figure 7 depicts the principal social aspects connected with on-site construction projects, based on 115 citations to examine the principal aspects related to sustainability KPIs in this dimension.The categories 'Labor', 'Community', and 'Customer Satisfaction' are the focal points, with 'Labor' accounting for 13% of citations and 'Community' for 10%.Indicators like 'Fair Salary', 'Equal Opportunity', 'Association', 'Working Hours', 'Work Load', 'Air Quality', 'Acoustic Comfort', 'Training and Development', and 'Complaints' each make up 3%, indicating a diverse range of social considerations in construction.Indicators cited at 2%-'Thermal Comfort', 'Occupational Health and Safety', 'Health Insurance', 'Reward', 'Labor Satisfaction', 'Turnover', 'Absenteeism', 'Efforts Against Corruption', 'Health, Safety and Environmental Hazards', 'Local Employment', 'Engagement with Community', and 'Community Complaints'-highlight the industry's focus on worker well-being, retention, and the impact on society.

Figure 7 .
Figure 7. Social aspects of on-site construction processes.Figure 7. Social aspects of on-site construction processes.

Figure 7 .
Figure 7. Social aspects of on-site construction processes.Figure 7. Social aspects of on-site construction processes.

Figure 8 22 Figure 8
Figure 8 presents the distribution of citation frequencies for economic indicators related to O-SCP that form the basis of sustainability KPIs, based on a total of 61 citations.'Cost' and 'Profit' are the predominant categories, reflecting their importance in economic evaluations with the highest citation frequencies of 18% and 8%, respectively.Identical citation frequencies of 7% for 'Raw Materials,' 'Packaging Materials,' and 'Fixed Assets'both buildings and office assets-indicate significant areas of expenditure in construction projects.Categories such as 'Utility', 'Training', 'Advertisement and Promotion', 'Revenue', and 'Subsidy or Tax Relief' are each cited in 5% of the dataset.Indicators with the lowest citation frequencies, at 3%, include 'Environmental Fines', 'Defective Products,' 'Research & Development', 'Depreciation', and 'Labor', which suggest areas of operational improvement and the impact of economic policies on construction profitability.

Figure 8 .
Figure 8. Economic aspects of on-site construction processes.

Figure 8 .
Figure 8. Economic aspects of on-site construction processes.

Sustainability 2024 , 22 Figure 9 .
Figure 9. Concept map of the classification of the literature review (the numbers correspond to the article codes shown in Table1).

Figure 9 .
Figure 9. Concept map of the classification of the literature review (the numbers correspond to the article codes shown in Table1).
Indicators of Mega Sustainable Construction Projects?A Stakeholder-Network Perspective A36 Sustainability Assessment of a Low-Income Building: A BIM-LCSA-FAHP-Based Analysis A37 A spatio-temporal framework for sustainable planning of buildings based on carbon emissions at the city scale A38 An analytical hierarchy based optimization framework to aid sustainable assessment of buildings A39 Sustainability framework for buildings via data analytics A40 Sustainability Performance of Green Building Rating Systems (GBRSs) in an Integration Model

Table 2 .
Source of publication: publication titles.

Table 3 .
Research streams considered in the selected articles.

Table 2 .
Source of publication: publication titles.

Table 3 .
Research streams considered in the selected articles.

Table 4 .
Sustainable aspects considered in the selected articles.

Table 5 .
Citation frequencies of research streams considered in the selected articles.

Table 6 .
Citation frequencies of sustainable aspects considered in the selected articles.

Table 7 .
Sustainability KPIs for environmental dimension.

Table 8 .
Sustainability KPIs for social dimension.

Table 9 .
Sustainability KPIs for economic dimension.