Linking the Development of Building Sustainability Assessment Tools with the Concept Evolution of Sustainable Buildings

: With the rapid development of materials science and construction technology, the concept of sustainable building (SB) and the Building Sustainability Assessment Tool (BSAT) have also evolved and developed. Understanding the development of BSAT and SB is of great signiﬁcance to the sustainable development of the construction industry. This research used the bibliometric method to analyze the development and evolution in the relevant literature on SB and BSAT from 1990 to 2021, and the correlations and differences between them were investigated. We found that there are many common trends in the development of research efforts in SB and BSAT: (1) they focused solely on the environment, in the early days, and only later considered economic and social impacts; (2) the scales with which they are concerned continue to expand, from individual buildings to communities and even cities; (3) key areas, such as energy, materials, resources, indoor environmental quality, high-tech applications, adaptability, and concern for people are being given more attention by both SB and BSAT. On the other hand, the difference between them is that SB research focuses on more macro aspects, such as policy, culture, climate change, while BSAT research is more concerned with micro aspects, such as its system of tools. Furthermore, some current research gaps in the BSAT ﬁeld are identiﬁed, clarifying its future research directions. By linking the evolution of the SB concept and the development of the BSAT research ﬁeld, this review provides a new and valuable perspective for the sustainable assessment of the construction industry, which, itself, is conducive to the sustainable transformation of this industry, which could contribute greatly to the mitigation of global climate change.


Introduction
Global warming, changes in rainfall patterns, extreme weather, etc. have had extensive and profound destructive effects on ecosystems and human survival, and some of these effects are increasing in frequency and intensity [1].The main reason for the occurrence and strengthening of these situations is human life and production activities [2].It is clear that, in order to meet the ever-increasing basic needs of the population on the basis of the limited resources of the planet, it is essential to develop a more sustainable development (SD) model for production, consumption and the economy as a whole.
The construction industry has made important contributions to economic prosperity and social development.At the same time, a large number of construction activities have brought enormous burdens to the environment, contributing to climate change.Research shows that the energy generated by the construction industry accounts for 40% of the total global energy consumption.It also contributes more than 30% of greenhouse gas (GHG) emissions [3].It is predicted that in the next 25 years, the emissions of the construction sector will increase faster than any other sector [4].The growing population and rapid growth of emerging economies mean that building energy demand will increase by 50% by 2050, and global building area is expected to double by then, which will undoubtedly continue to increase building energy consumption and related gas emissions [5].Therefore, the construction industry is considered to be the most promising sector for rapidly transitioning to SD [6].
Achieving SD is not an easy task, and corresponding assessment tools, technical measures, drivers, action plans, indicators, etc. are essential [7]; for the SD of the construction industry, the use and promotion of building sustainability assessment tools (BSAT) is a vital part of promoting sustainable building development [8][9][10].These BSATs originated in Europe and quickly developed into North America, Asia, and then became very popular around the world [11,12].It is believed that there are more than 600 different BSATs in the world, and this number is increasing [13][14][15][16].
In fact, the concept of SD is constantly changing and evolving with the development of technology, materials and people's concerns, and the same is true for the sustainable development of buildings [17,18].As an important tool for assessing the sustainability of buildings, BSAT is continuously upgraded and updated at the same time.And the changes in BSAT can reflect the development of the concept of "sustainable building" (SB) from an important perspective [19].Therefore, the study on the development of the SB concept and the evolution of BSAT is very important in the realization of SD within the construction industry.This review will focus on the evolution of the concept of SB and the development of BSAT through an analysis of the existing literature and a study of the relevance of the two.
There are many studies on the changes in the concept of SD [17,20,21].However, the number of studies on the evolution of SB and the development of BSAT is relatively small, and systematic research on the correlation between the two is even more rare.However, this kind of research has great theoretical and practical significance, as, by studying the evolution of the concepts and tools of SB, people will be more aware of their changes and latest trends and it is critical to achieving building sustainability goals [22].At the same time, it can provide more clear and scientific guidance for the future development of these BSATs.
The objectives of this review are: • Review the formation and development of the SB concept.

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Explore the evolution and development trends of different types of BSAT.

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Correlation analysis between the development of the SB concept and the evolution of BSAT.

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Make recommendations for future BSAT research.

Research Methods
The research process of this study is divided into three steps (Figure 1): • Analysis of the related literature on SB and its development.

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Review of the related literature on BSAT and its evolution.

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Comparison and comprehensive analysis of the former two.
lyzed using bibliometric visualization methods.The aim was to understand the research from earlier circumstances to grasp the current status of this research, and to determine the common patterns and trends therebetween.

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A deeper perspective, in which are screened-out the representative and influential papers directly related to these concepts' development and analyze them in depth.

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Comprehensively analyze the development of SB and the evolution of BSAT and find their relevancies and deviations.

Bibliometric Visualization
Bibliometric visualization has been applied in many fields as a scientific literatureanalysis tool.In recent years, some researchers have used this method to study SB-related fields.From the object of analysis, some studies have analyzed the literature of SD using bibliometric visualization [23,24], while some studies used this method to study sustainable cities and communities [25][26][27][28].However, the number of studies using this method to analyze SB is small [29][30][31][32].From the content of the analysis, most of them are analyzed along criteria such as authors, institutions, countries, number of papers and so on; there are few analyses on the fields and topics themselves.
In addition, their data sources, analysis software and time periods are different, and the analysis content is also different, leading to different analytical results.After analyzing these studies, some problems therein were discovered.

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Their numbers of samples are insufficient.

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Their selected keywords are inappropriate.

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There is no in-depth analysis of the evolution and trends of SB.

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Their time periods do not cover recent years.
In order to avoid the above problems and prevent the duplication of research, this paper will focus on the evolution and trends of SB-related literature from the perspectives of fields, topics, and keywords.
The bibliometric software used in this article is Citespace due to its functions, such as time-slicing and burst-detection [25], which fit the requirements of this study.We chose Web of Science (WOS) as the database because it is the largest accessible citation database, and it has better compatibility with Citespace.

Selection of Keywords for Search
According to the requirements of the three-level analysis, this research divides the relevant keywords into four categories (Table 1).Furthermore, the review of SB-and BSAT-related literature is divided into three levels, by which the research status, research trends, and representative papers are analyzed separately.

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A holistic perspective.The SB-and BSAT-related literatures were scientifically analyzed using bibliometric visualization methods.The aim was to understand the research from earlier circumstances to grasp the current status of this research, and to determine the common patterns and trends therebetween.

•
A deeper perspective, in which are screened-out the representative and influential papers directly related to these concepts' development and analyze them in depth.

•
Comprehensively analyze the development of SB and the evolution of BSAT and find their relevancies and deviations.

Bibliometric Visualization
Bibliometric visualization has been applied in many fields as a scientific literatureanalysis tool.In recent years, some researchers have used this method to study SB-related fields.From the object of analysis, some studies have analyzed the literature of SD using bibliometric visualization [23,24], while some studies used this method to study sustainable cities and communities [25][26][27][28].However, the number of studies using this method to analyze SB is small [29][30][31][32].From the content of the analysis, most of them are analyzed along criteria such as authors, institutions, countries, number of papers and so on; there are few analyses on the fields and topics themselves.
In addition, their data sources, analysis software and time periods are different, and the analysis content is also different, leading to different analytical results.After analyzing these studies, some problems therein were discovered.

•
Their numbers of samples are insufficient.

•
Their selected keywords are inappropriate.

•
There is no in-depth analysis of the evolution and trends of SB.

•
Their time periods do not cover recent years.
In order to avoid the above problems and prevent the duplication of research, this paper will focus on the evolution and trends of SB-related literature from the perspectives of fields, topics, and keywords.
The bibliometric software used in this article is Citespace due to its functions, such as time-slicing and burst-detection [25], which fit the requirements of this study.We chose Web of Science (WOS) as the database because it is the largest accessible citation database, and it has better compatibility with Citespace.

Selection of Keywords for Search
According to the requirements of the three-level analysis, this research divides the relevant keywords into four categories (Table 1).

The Principle for Determination Keywords
The determination of these keywords follows the principle (Figure 2); The selected keywords can: • cover all relevant fields to ensure the comprehensiveness of the search results;

The Principle for Determination Keywords
The determination of these keywords follows the principle (Figure 2); The selected keywords can:

The Selection Criteria for Papers
This review mainly covers related academic papers from 1990 through 2021 and has obtained a large number of different research works through search.In order to ensure the accuracy and quantity of the samples, the results of the search were screened objectively.The main selection criteria are as follows:

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The research paper should be relevant to the objectives of this study, that is, related to the BS concept and BSAT development.

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Book chapters and revoked articles are excluded.

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The paper is written in English.

The Development of SB
SB originated in the late 20th century [33].Hill et al. [34] studied the concepts of "sustainability" and the "sustainability of buildings" in 1994.However, the focus of this research was on the formation and development of sustainability rather than the sustainability of buildings.Cassidy et al. [35] wrote a research report on the development of SB in 2003.The report details the history of SB, but mainly presents some related milestones and does not study the changes in the concept itself.

The Selection Criteria for Papers
This review mainly covers related academic papers from 1990 through 2021 and has obtained a large number of different research works through search.In order to ensure the accuracy and quantity of the samples, the results of the search were screened objectively.The main selection criteria are as follows: • The research paper should be relevant to the objectives of this study, that is, related to the BS concept and BSAT development.

•
Book chapters and revoked articles are excluded.

•
The paper is written in English.

The Development of SB
SB originated in the late 20th century [33].Hill et al. [34] studied the concepts of "sustainability" and the "sustainability of buildings" in 1994.However, the focus of this research was on the formation and development of sustainability rather than the sustainability of buildings.Cassidy et al. [35] wrote a research report on the development of SB in 2003.The report details the history of SB, but mainly presents some related milestones and does not study the changes in the concept itself.
Krizankova et al. [36] summarized the development of building sustainability into four decades: The first decade, from the early 1970s to the early 1980, was the initial exploration period for building sustainability.Two oil crises in this period prompted people to reexamine the energy and waste of buildings, and people actively experimented with new forms of energy in buildings.
The second decade, from the early 1980s to the early 1990s, was a time when some building sustainability measures moved from the laboratory into practice, and some improved building techniques were used in larger and more complex buildings.
In the third decade, from the early 1990s to the early 2000s, the concept of SB was clarified, during which time many milestones in the history of SB development occurred.
In the fourth decade, from the early 2000s to the early 2010s, the concept of building sustainability was extended to almost all other human-related areas.The European Union released "Architecture and Sustainability" in 2009, and the European Energy Directive was also released in 2010.
Obviously, due to the limitations of the writing era, the study did not take into account the SD of buildings in recent years.In addition, it is not very clear that the 'decade' is properly a phase reflecting the actual situation.This analysis puts the main focus on the factors of time.
[37] divided the development of the concept of building sustainability into four periods: The concept of SB began to emerge, with particular emphasis on the energy efficiency of buildings.

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Period 2 (1990-1999): The building sustainability assessment tool was born and began to have an impact on the SD of the building, with special emphasis on the environmental impact of building materials.

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Period 4 (2010-2017): Taking the EU directive on building energy performance as a milestone, the energy performance of buildings began to receive significant attention.
In the WOS, the Class A keywords were searched by topic, and 6994 results were retrieved.Through the screening principles mentioned above 6158 documents closely related to SB were selected.These documents were then analyzed using Citespace.

The Literatures Related to SB
The study of SB began in 1990 and has continued for 31 years, to the present day.The study identified a total of 6158 valid documents, indicating that SB is a topic of continuous attention (Figure 2).The number of studies on SB in the first 15 years was not large (within 100 articles per year), and the growth was slow.In the last 16 years, the literature related to SB has increased rapidly, and most of the selected literature was published during this period.Specifically, the change in the number of SB studies can be divided into five phases: • Phase 1 (1990-1997), the number of studies per year is small; all have single-digit counts.

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Phase 5 (2015-2021), the number of studies continues to increase, and the rate of increase is further increased.

Category Analysis of the Literature
As shown in Figure 3, the categories of these documents were analyzed using Citespace.Each circle represents a category, blue represents SB involved in this category very early, and red indicates that SB research still exists in this field until today.The blue line represents the early stage of 1990-1999, the green line represents the mid-term of 2000-2010 and the yellow and red lines represent the near-term stage after 2010.The larger the diame-ter of the circle, the greater the number of SB-related documents in the category, and the more the color gradation of the "annual ring", the longer the SB lasts in the category.

Category Analysis of the Literature
As shown in Figure 3, the categories of these documents were analyzed using Citespace.Each circle represents a category, blue represents SB involved in this category very early, and red indicates that SB research still exists in this field until today.The blue line represents the early stage of 1990-1999, the green line represents the mid-term of 2000-2010 and the yellow and red lines represent the near-term stage after 2010.The larger the diameter of the circle, the greater the number of SB-related documents in the category, and the more the color gradation of the "annual ring", the longer the SB lasts in the category.These SB-related literatures cover more than 30 categories.The categories with the most literature are "Engineering", "Construction and Building Technology", and "Engineering Civil", and these categories have a long time span.In addition, "Architecture" and "Engineering and Fuels" have a long-time span, and they are all areas that were originally involved in SB research.
The categories "Environmental Science and Ecology", "Green and Sustainable Science and technology", and "Science and Technology-other topics" also contain a large number of documents, and they all appear in the medium term.
It is worth noting that the categories of "Management", "Business and Economics", "Computer Science", "Material Science", "Chemistry", "Physics", "Multidisciplinary Science", etc., although they have a small number of documents, they mainly appear in the near-term.This shows that SB research is developing in these areas.
In short, SB-related research initially focused on the fields of construction, engineering and architecture, and subsequently developed into environmental sciences, sustainable technologies and other fields.In recent years, it has expanded into more fields, such as management science, computer technology, and materials science.The overall trend is that SB has become a multidisciplinary and integrated research topic.

Evolution of the SB
First, through analysis and collation, these documents related to SB development are divided into different categories of perspective: the local, technical, external, case, special, global, and tool perspectives (Table 2).The local perspective involves the development, progress, trends, materials, and technology of SB in a specific country or region, having a long-time span and covering the aforementioned Phases 2-5 of the SB development stages.These SB-related literatures cover more than 30 categories.The categories with the most literature are "Engineering", "Construction and Building Technology", and "Engineering Civil", and these categories have a long time span.In addition, "Architecture" and "Engineering and Fuels" have a long-time span, and they are all areas that were originally involved in SB research.
The categories "Environmental Science and Ecology", "Green and Sustainable Science and technology", and "Science and Technology-other topics" also contain a large number of documents, and they all appear in the medium term.
It is worth noting that the categories of "Management", "Business and Economics", "Computer Science", "Material Science", "Chemistry", "Physics", "Multidisciplinary Science", etc., although they have a small number of documents, they mainly appear in the near-term.This shows that SB research is developing in these areas.
In short, SB-related research initially focused on the fields of construction, engineering and architecture, and subsequently developed into environmental sciences, sustainable technologies and other fields.In recent years, it has expanded into more fields, such as management science, computer technology, and materials science.The overall trend is that SB has become a multidisciplinary and integrated research topic.

Evolution of the SB
First, through analysis and collation, these documents related to SB development are divided into different categories of perspective: the local, technical, external, case, special, global, and tool perspectives (Table 2).The local perspective involves the development, progress, trends, materials, and technology of SB in a specific country or region, having a long-time span and covering the aforementioned Phases 2-5 of the SB development stages.The technical perspective relates to the potential impact of specific materials and technologies on the development of SB, covering the aforementioned Phases 3-5.The external perspective involves factors such as driving forces, obstacles, and policies that affect the development of SB, covering the aforementioned Phases 4-5.The case perspective mainly analyzes the development of SB through actual cases, covering the above-mentioned Phase 5.The special perspective mainly discusses specific topics, such as environment, economy, society and culture in the development of SB, covering the above-mentioned Phases 3-5.The global perspective mainly investigates the development and trend of SB from a global scale, covering the above-mentioned Phases 4-5.The tool perspective mainly refers to the analysis of the development of SB through the research of BSAT, covering the above-mentioned Phases 4-5.A large amount of research concerns the development of SB in a specific country [38][39][40], and the development of BSAT in a particular country [91,98].In addition, there are many studies on materials, technology, and SB development [99][100][101].In recent years, there have been many documents on factors affecting SB development, such as driving forces, obstacles, policies, and laws [61][62][63][64].Some studies are about the "three pillars" of the environment, society and economy, but the number is small [76,77], though research on the evolution of SB and BSAT is a hot topic in recent years [64,74,83,102].The main reason for this is that both SB and BSAT have experienced 31 years of development; thus, now is a good time to summarize them.However, there is not much comprehensive and in-depth research in this field.By analyzing the citation bursts of the topics and keywords of these SB-related literatures (Figure 4), combined with some SB development-related studies, the SB research hotspots and trends were discovered as follows.

The Evolution of the "Three Pillars"
It is clear that SB was originally thought to be a building method that minimizes environmental impact.In the early stages, keywords such as "environmental" and "environmental assessment" appear frequently [103][104][105][106]. Then the frequency of economic-and social-related keywords, such as "cost", "economic analysis" and "social impact", began to increase.Therefore, SB has shifted from its initial focus on the environment to focusing on the "three pillars" [32,107,108].However, some researchers have suggested that the development of the three pillars of SB is not balanced, in that the environment has received greater attention, while the social and economic aspects have not received the attention they deserve [31,84,109,110].
Zuo et al. [111] pointed out that the social dimension is the weakest link of SB, which is largely ignored.In addition, Doan et al. [112] claimed that the institution and leadership are the fourth pillar of SB, and they believe that SB will have more pillars in the near future.

Concern for Climate Change
In the middle of the development of SB, when attention to climate change increased sharply, "carbon emissions", "carbon footprint" and other keywords related to greenhouse gas emissions frequently appeared.This phenomenon continues to this day [31, 109,113].Many studies recognize the enormous contribution of architecture to climate change [3,114].Greenhouse gas emissions throughout the life of the building are considered to be one of the most critical SB assessment indicators [6,115,116].

Resources and Materials
Resource utilization efficiency was regarded as one of the core indicators of SB in the early stage [106,117,118], and resources and materials have always been the hot spot for studying SB [110,114,119,120].It is worth noting that researchers then began to have a greater interest in "waste", "recycle material", "water", etc., and then the frequency of keywords related to construction materials, such as "concrete" and "hemp", increased.This shows that research has expanded from focusing on material use and material recycling to material properties and new materials.However, there are also different opinions.Darko et al. [31] proposed that the contents of "sustainable concrete" and "renewable resources" in SB research have not received sufficient attention.

Indoor Environmental Quality (IEQ)
"Daylight" was paid attention to at an early stage.After that, "air quality", "visual", "thermal comfort", and "indoor environmental quality" have appeared more and more frequently, especially in recent years [31, 109,121].However, Abdellatif and Al-Shamma'a [122] pointed out that there is still a knowledge gap in the field of improving the indoor environment and establishing user perception, and further research in this field is needed.

Concern for People
SB's attention to people has generally experienced changes from "health" to "comfort" and "satisfaction" [31,123].On the one hand, research pays more and more attention to the influence of SB on people.On the other hand, it also reflects a trending change from physical impacts to psychological impacts on people.Wuni et al. [29] pointed out that "attitude assessment" and "post-assessment" have become one of the top ten SB research hotspots.Zuo and Zhao [109] pointed out that SB's research has shifted from focusing only on construction itself to the interaction between buildings and users.Marjaba and Chidiac [124] pointed out that people's health and environmental awareness is the most important driving force for SB development.On the other hand, Yuan and Zuo [125] suggest that SB should pay attention to health, safety, comfort, and accessibility.Berardi [110] also pointed out that SB should pay more attention to people's well-being, user satisfaction and other aspects.

Technical Aspects
Although most studies have found that advanced technologies related to SB are a wide range of research areas [29,30,109].However, some people disagree, and Darko et al. [31] pointed out that there are obvious shortcomings in topics such as "sustainable concrete" and "integrated advanced technology" in SB research.According to the findings of this study, SB focused on energy technologies, such as "photovoltaic technology", in the early stage, and then turned to green construction technologies, such as "prefabricated technology", "enclosure structure", and "green roof".It should be said that "advanced technology" has always been a research focus and a research trend.

Different Scales
SB has experienced a leap from "sustainable building" to "urban", "community", "urban" and then "infrastructure".SB no longer likes to focus on the building itself, and is beginning to grow toward a larger and more complex level [126].The expansion to a larger scale has had a positive impact on the development of SB, because buildings are often inseparable from the surrounding environment and facilities.Larger assessments in communities or cities will involve broader and more complex factors, fro which the accuracy of results will be greatly increased [110].Yet, Pan and Ning [113] pointed out that research on SB at the community or city levels is not enough.However, the study clearly did not take into account the latest research trends.Ghoddousi et al. [127] also pointed out that research on the use of sustainability in infrastructure is not enough.

Adaptability and Resilience
SB's adaptability includes many aspects, including adaptability to climate change, adaptability to different geographical backgrounds, adaptability to dynamic needs, etc. [109,126,128].Improving the building's adaptability and resilience has become a topic of increasing concern because it ensures the building's ability to maintain and metabolize for a long time [110,129].

Culture and Aesthetics
At present, SB pays little attention to related aspects such as "aesthetics" and "culture", while some studies point out that it is important to combine humanities, aesthetics, culture, and SB [126,130,131].Berardi [110] emphasized improving aesthetics and preserving cultural values as important attributes of SB.The survey by Su and Lin [132] also found that it is important to include humanities and aesthetics in the SB.Chehrzad et al. [131] pointed out that the challenge of integrating aesthetics and cultural aspects into SB is that the indicators that can characterize them are mostly qualitative and highly dependent on expert judgment, resulting in uncertainty about the objectivity and accuracy of such evaluations.

Innovation
Under the influence of the expected climate change and resource shortage in the future, the imperatives of social change and technological innovation have furnished SB with huge opportunity for innovation and development [133].Some studies also show that SB is paying more and more attention to innovation [109,131].Shan and Hwang [14] believe that the introduction of innovation points can encourage, recognize and reward those measures that can prompt SB to find new breakthrough points and development fulcrums in technology, design, and process.

Project Management
Although many studies have shown that the delivery and management of SB projects has gradually become a research area of SB hotspots [22,29], but Darko et al. [31] pointed out the lack of "project management"-related content in SB research.In fact, SB does have shortcomings in project management during the implementation process [134,135].Due to this, there is much research on this topic.Wu and Low [118] suggested that project management should be considered both in terms of process and practice while meeting green requirements.

Factors Affecting Development
Green building codes, policies and regulations are important guarantees and a basis for the development of SB, so such topics have received much attention [29,136,137].
"Barriers", "Drivers", "Success Factors", "Risks", etc. are frequently used keywords in recent years.These aspects are also some of the topics of most concern in the development of SB [62][63][64][66][67][68].However, Ahmad et al. [22] pointed out that the current research on these topics is fragmented, which may hinder the further development of SB.Zuo and Zhao [109] suggested that research should be strengthened in areas such as SB policies and incentives.
In addition, since "communication" and "cooperation" are also crucial to the development of SB, many studies suggest that international cooperation should be strengthened to promote SB development [31,138,139].Pan and Ning [113] argued that SB research does not combine end-user perspectives with the perspectives of relevant professionals, and there are significant information and communication gaps between multiple stakeholders.

The Evolution of BSAT
BSATs aim to measure and assess compliance with sustainability principles, reduce the environmental burden of the buildings they prescribe, and mark them accordingly.Sustainability rating tools are especially important in distinguishing the level of building sustainability [140,141].
Wen et al. [102] divided the evolution of global BSATs into three stages, based on their sustainability concerns.
• Phase 1 (1990-1997), the initial development period; the number of BSATs is relatively small.Moreover, the keywords in 356-item BSAT-related literature review were statistically and categorized.It was found that most of the literature is about BSAT assessments, where "energy" and "environmental impact" are the most frequently occurring keywords.Second, there are many keywords related to technology, development, and tools.Furthermore, some common topics and related opinions in the development of BSAT are identified as follows.
4.1.1.The Evolution of the "Three Pillars" Similar to SB development, BSAT is also undergoing a process from environmental to social and economic expansion [107,138,142].Khan et al. [114] have recommended combining BSAT with life-cycle costing to determine the various economic costs associated with SB.Martek et al. [107] found that some social equity-related content, such as affordable housing, convenient public facilities, quality of the work environment, etc., are entering BSAT.Zuo and Zhao [109] believe that the integration of economic, social and other aspects in the BSAT indicates that people are more and more accepting the "triple bottom line".However, Illankoon et al. [143] found that almost all BSAT's focus on social sustainability focused on health and well-being, while other social aspects were rarely considered, and they pointed out that BSAT largely ignored economic sustainability.A recent survey by Wen et al. [102] shows that the consideration of environmental indicators in the development of BSAT continues to decline, while social indicators and economic indicators have a slight upward trend.

Energy and Resources
The efficient use of energy performance and resources has always been the focus of BSAT [6,14,131,144].In fact, BSAT development was originally based on a single, energyrelated parameter.However, this assessment, along a single dimension, has received much criticism because it cannot assess complex sustainability [139].In addition, there are many studies that have cast doubt on the energy performance and resource usage of BSAT-certified buildings [12,145].

LCA
As an important tool and method, LCA has always been a hot topic in BSAT research.Due to LCA's comprehensive and systematic environmental assessment methodology, LCA tools are integrated, to varying degrees, in many green building-rating systems [146,147].Many studies have pointed out that there is great potential to combine LCA with BSAT [17,114,148].The main advantage of integrating LCA with BSAT is in helping to create a robust quantitative assessment method [138].Some studies explore ways to integrate LCA into BSAT [149].However, Ismaeel [150] pointed out that LCA is only partially integrated by BSAT and is not reflected at the overall-system level.

System Aspect
The BSAT system has been extensively studied."Assessment indices", "criteria", "indicators", etc. are the most common keywords for studying BSAT systems.The indicator system is the core aspect of the BSAT and is critical to the legitimacy of the BSAT [151].The development of the building sustainability indicator system has two forms; one is top-down and developed by the government based on expert opinions [152].The other is bottom-up-it is dominated by the public [153]-but this important system has been fiercely questioned because of its subjectivity and irrationality [154][155][156].

Compare Research
As shown in Table 3, a large number of comparative studies have been carried out on the BSAT indicator system at different levels, including categories, subcategories, criteria, and indicators [10].Among them, the number of studies on the criteria level is the largest, and they focus on the weight comparison of different levels of indicator systems.Li et al. [157] divided these comparative studies into general, categorical, criterion, and indicator comparisons according to the research objects.On this basis, Wen et al. [102] collectively referred to these studies as horizontal comparative studies and pointed out the lack of adequate longitudinal research in the BSAT field.Moreover, according to Liang et al. [16], there are five problems in the literature related to the comparative study of BSAT:  [170] 19 [171] 4.1.6.Technology Integration and Innovation Advanced information and communication technologies will play a key role in helping to develop green buildings, while "Building Information Modeling", "Artificial Intelligence", "big data", etc. appear more frequently.This shows that the development of BSAT is being combined with the latest technology [109,128,172].On the other hand, Darko et al. [31] believe that future research should be more extensively conducted on the collection of advanced technologies, such as BSAT and AI and big data.Lu et al. [58] pointed out that there are still many weak links that need to be overcome when combining BIM with BSAT.In addition, BSAT's innovation has received increasing attention in recent years [14,131].

Concern for People
The frequency of keywords such as "thermal comfort", "visual comfort", "health", and "indoor environmental quality" is strengthening [173][174][175].Like SB's development trend, BSAT is also strengthening its focus on human comfort and health [14,109,128,131,176].However, some studies have expressed different views.Gou et al. [177] pointed out that BSAT has great challenges in IEQ because it defines the physical environment relatively narrowly, affecting the perception and satisfaction of occupants.Xue et al. [178] also pointed out that BSAT ignores the type of building and the associated needs of different occupants.Yeang [179] pointed out that BSAT has not fully met the user's "health" standard."Green" buildings are no more productive than those that are reasonably designed, because indoor environmental quality and methods of measuring actual productivity are inaccurate [180].
On the other hand, Zuo and Zhao [109] also pointed out that BSAT needs to pay more attention to special populations such as the elderly, students, and teachers.

Expanded Scale
Although BSAT focuses on the sustainability of buildings, such as schools, hospitals, residential buildings, commercial buildings, data centers, etc. [31], it also strides toward other larger scales, such as the "city," "community," "urban," "infrastructure," and so on [166,[181][182][183].However, Wu et al. [184] pointed out that little research has been conducted on how to effectively transition green buildings to green communities.By analyzing LEED ND, they found that their economic, social and environmental credit allocations were uneven.

Different Phases
At the beginning of BSAT development, more attention was paid to the design phase, although some studies indicate that BSAT may play the biggest role in the design phase [33,185].Yet it has also been criticized for the lack of an overall life-cycle perspective [138,186,187].It is a fact, however, that BSAT is developing into the entire life-cycle and gradually achieving coverage for design, construction, operation, and demolition [12].Still, some studies indicate that most green buildings are only certified at the design stage, while green certification at the operational stage is rare [163,188].

Adaptability
BSAT's flexibility is critical to its adaptability [110].Numerous studies have confirmed that most BSATs are designed according to local climate and geographical conditions [105,158,189,190].BSATs' adaptability to climate change and different geographical characteristics needs to be strengthened [191][192][193][194]; this will be an important direction for its development [128,144].Some studies suggest that BSAT should assign weights for various credits based on local and regional conditions.This process should reflect the cultural characteristics of different countries and regions [12,139,166].In addition, some commercial BSATs have also gained attention to the market [97].4.1.11.Ease of Use Some studies have found that some users think that BSAT is too complicated and takes too long to use [12,139,195], restricting their promotion and development.Kaatz et al. [192] accused BSAT of technical language barriers to users.Therefore, the importance of the simplicity and ease of use of the BSAT system is emerging [114].This requires BSAT to be user-friendly and easy to operate [110,196].

Research Findings
This review analyzed previous literature related to SB and BSAT and discussed the development of the SB concept and the evolution of BSAT.After that, the contributions and limitations of the relevant researchers were evaluated.The final goal is to find out the relevance of the development direction of SB and BAST and to find the knowledge gap in this research area.We hope to provide reference for future-related research.
This review used the bibliometric method to analyze 6158 SB-related works and 356 BSAT-related works.Subsequently, based on the appropriate combination of keywords in the literature search, 108 and 47 documents related to the evolution of SB and BSAT were further identified and analyzed in depth.The evolution of and correlations between the two emerged (Figure 5).The specific findings follow.

Commonalities between the Development of SB and BSAT
• Both SB and BSAT initially focused on environmental impacts and then began to focus on social and economic aspects.However, the current social and economic concerns are not enough, and this will be a long-standing topic of debate in the future.

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Energy performance and resource efficiency have received the greatest attention from SB and BSAT, and have an important position in the entire development process of SB and BSAT.

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SB and BSAT initially focused on the sustainability of building units, and both of them turned their attention, later, to a larger scope, e.g., beginning to pay attention to the sustainability of communities and cities.

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The interest of SB and BSAT in IEQ is increasingly growing, and this trend has be-

Commonalities between the Development of SB and BSAT
• Both SB and BSAT initially focused on environmental impacts and then began to focus on social and economic aspects.However, the current social and economic concerns are not enough, and this will be a long-standing topic of debate in the future.

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Energy performance and resource efficiency have received the greatest attention from SB and BSAT, and have an important position in the entire development process of SB and BSAT.
• SB and BSAT initially focused on the sustainability of building units, and both of them turned their attention, later, to a larger scope, e.g., beginning to pay attention to the sustainability of communities and cities.

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The interest of SB and BSAT in IEQ is increasingly growing, and this trend has become more apparent in recent years.

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Both SB and BSAT are more and more concerned about people.From the beginning, SB and BSAT mainly focused on physical aspects, such as sunlight and health, and now is increasingly focusing on psychological aspects, such as user experience and satisfaction.

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Adaptability is receiving more and more attention.The SB focuses on adaptability to climate change, different geographies, and changing needs, while the BSAT focuses on improving resilience to different geographies through a flexible indicator system.

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The use of high technology and the encouragement of innovation are common trends in the development of SB and BSAT.SB's integration of high technology lies mainly in green construction technologies, while BSAT's focus on high technology is in information technologies, such as artificial intelligence and big data.

Personality Trends in SB Development
Project management, culture, aesthetics, climate change, etc. are all trends in the development of SB.In addition, SB is also concerned with factors that affect its development, such as drivers, obstacles, policies, regulations, and so on.These topics are relatively rare in the study of BSATs.

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BSATs initially focused only on the design phase, and later began to consider other stages of construction, renovation, renovation, etc., to cover the entire life cycles of buildings.

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A comparative study of different BSATs is a hot topic, where indicator systems and weights are the focus of comparison.

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Critical analysis of the BSAT system is a research trend because of the subjective nature of its indicator system.

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The ease-of-use of a BSAT has also received a lot of attention because it directly affects its promotion and development.

Relevance and Difference between SB and BSAT Development
There are many common trends and research areas in the development of SB and BSAT, but there are also some differences.Aspects of SB's focus are more on macro aspects, such as policy, culture, and climate change.The study of the BSAT focuses more on micro aspects, such as the system of tools, ease of use, and so on.The development of SB provides a broader topic, while BSAT research operates more at the application and operational levels.

Conclusions
There has been much research on SB and BSAT before this work (6158 and 356 related documents were identified, respectively), and the analysis angles thereof are different, but they have played a positive role and contributed to the development of SB and BSAT.Yet, by analyzing these documents, some research gaps were discovered.Although the study of SB and BSAT development has great significance, the research on both of the topics is obviously insufficient (only 108 and 47 related documents were identified, respectively).The number of such studies has increased in recent years, but most studies are not deep enough in their analyses.Many studies focus on one of SB or BSAT, and there are few studies on the correlation and differences between SD, SB, and BSAT development.
There are deficiencies in the research methods for studying the BSAT.Most studies have not developed a unified assessment framework for different BSATs, resulting in insufficient accuracy of results.Many studies have focused on the balance between the "three pillars" of SB and BSAT, but there is little research on the balance between generations and fairness.
Understanding the development of BSAT and SB is important for the sustainable development of the construction industry and for global climate change.This paper reviewed the relevant literature for SB and BSAT from 1990 through 2021, discussed the development of the two, and analyzed the correlations and differences between them.Since this review was based on an analysis of previous literature, its results are directly related to the selected sample, which may also result in some gaps, with respect to the actual situation.It is suggested that, in the future, more direct research on the evolution of BSATs themselves, in different historical periods, should be carried out.

Figure 1 .
Figure 1.Research process of the study (source: original).

Figure 1 .
Figure 1.Research process of the study (source: original).

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cover all relevant fields to ensure the comprehensiveness of the search results; • exclude irrelevant and subjective keywords to ensure the accuracy of search results; and • ensure the relevance of search results to the research field through the combination of different categories of keywords and the flexible selection of search methods, such as WOS titles and topics.

Figure 2 .
Figure 2. Combination of the keywords in the literature search (source: the authors).

Figure 2 .
Figure 2. Combination of the keywords in the literature search (source: the authors).

Figure 3 .
Figure 3. Category analysis of the literature (source: the authors).

Figure 3 .
Figure 3. Category analysis of the literature (source: the authors).

8 of 23 23 Figure 4 .
Figure 4.The strongest citation bursts of keywords (source: the authors).Figure 4. The strongest citation bursts of keywords (source: the authors).

Figure 4 .
Figure 4.The strongest citation bursts of keywords (source: the authors).Figure 4. The strongest citation bursts of keywords (source: the authors).

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providing equal conditions of comparison; • giving specific calculation methods; • establishing a unified index classification framework; • clarifying the classification process of indicators; and • considering the multidimensional properties of indicators.

Table 1 .
Keywords used for searching.
• exclude irrelevant and subjective keywords to ensure the accuracy of search results; and • ensure the relevance of search results to the research field through the combination of different categories of keywords and the flexible selection of search methods, such as WOS titles and topics.

Table 1 .
Keywords used for searching.

Table 2 .
Different categories of documents related to SB development.

Table 3 .
Analysis of BSAT comparative literature.