Critical Success Factors for Sustainable Construction Project Management

: It is necessary to identify critical success factors (CSFs) that a ﬀ ect the construction process. This paper’s aim is to deﬁne the CSFs considering views of all construction project stakeholders. The contribution of this paper is to categorize project success factors into categories and quantify the e ﬀ ect of each category taking into account the e ﬀ ect of all stakeholders on project e ﬃ ciency and progress. To achieve this objective, a comprehensive literature review was carried out. After literature review, 40 success factors were compiled into seven categories: project-related factors, company- and work-related factors, client-related factors, project management factors, design-team-related factors, contractor-related factors, project-manager-related factors. Consequently, a survey including these listed success factors was prepared and distributed to various experts in the construction ﬁeld to be ranked; 148 responses were received. Employing the Relative Importance Index (RII) and traditional Analytic Hierarchy Process (AHP) method with Saaty random index that prioritizes these CSFs, the collected data were analyzed after receiving responses. Even though there were disagreements in stakeholders’ views and their goals, signiﬁcant areas have been identiﬁed as project ﬁnancial issues, managerial aspects, and authorities’ approval mechanism. The outcome of this paper would be used by construction industry professionals to support, evaluate, and measure the success of projects for better allocation of resources.


Introduction
Performance is a critical concern and the success of the construction projects will face several challenges during project delivery. A lot of researchers in the project management area have studied critical success factors (CSFs) in projects [1][2][3][4][5]. However, the concept of project success and performance metrics is still ambiguous, and this is due to variations in expectations of project success among stakeholders of various projects in a project. Therefore, there is a gap in studying all relevant factors that affect performance of projects considering the perception of success by project stakeholders.
The main objective of this paper is to identify the CSFs that contribute to the project success. The major contribution of this paper is to categorize project success factors into categories and quantify the effect of each category on project performance and success considering all project stakeholders. This study is different from the others in the literature because it considers the effect of project stakeholders on project success. Factors from past research were gathered and compiled under seven categories, namely, project-related factors, business-and work-environment-related factors, client-related factors, project management factors, design-team-related factors, contractor-related factors, and project-manager-related factors. A survey including these listed success factors was Table 1. Seven categories and 40 critical success factors (CSFs) with respect to their relevant references.

I. Project-Related Factors
Reference No.
This work leads to the collection and study of the project success factors with the integrated AHP. This study tried to overcome the assessment of project critical success factors by AHP. This research is distinct from the others in the literature because it takes into consideration the impact of project stakeholders on project performance.

Methodology
This research mixes qualitative and quantitative research methods. This method is based on KBT (Knowledge-Based Theory) and it has three steps: (1) identification of factors that affect project success, (2) survey, and (3) RII and AHP analyses. KBT is embedded and carried through multiple entities Sustainability 2020, 12,1990 4 of 17 including organizational identities, systems, and employees with the tool of the literature review and a questionnaire. A questionnaire was designed for the business professionals' opinions of the CSFs. The first section of the questionnaire includes questions on respondents' background. Categorizing respondents on the basis of their type of organization would also give an idea of the understanding of CSFs by each category. The 40 factors listed in this section have been grouped into seven groups based on literature review, with different success factors in each category. The weighting scale was designed and consisted of 1 to 9 ratings, where 1 was the project's no significant impact on project success and 9 was the project's highest impact on project success.
In order to measure the significance of different factors, the relative importance index formula was used. Then, the ranking values obtained from RII were used for the AHP analysis. This is a new way of use of AHP by transferring values from RII to AHP. Due to its great flexibility and broad applicability, AHP has been extensively implemented for the last 20 years [60]. The study by [61] reviewed 77 AHP-based papers published in eight peer-reviewed journals in order to better identify and delineate AHP implementation areas and problem-solving decision-making within the field of construction management. The study revealed that AHP is versatile and can be used either as a stand-alone tool or in combination with other tools to solve problems in building decision-making. Several authors have used AHP for the coordination and review of complex decisions [62][63][64]. This study tried to overcome the decision-making of assessment of project critical success factors by AHP. The methodology can be seen in Figure 1 below. construction management. The study revealed that AHP is versatile and can be used either as a standalone tool or in combination with other tools to solve problems in building decision-making. Several authors have used AHP for the coordination and review of complex decisions [62][63][64]. This study tried to overcome the decision-making of assessment of project critical success factors by AHP. The methodology can be seen in Figure 1 below. A total of 148 complete surveys were collected. Relative importance index and Analytical Hierarchy Process were used as statistical tools to rank CSFs. Recommendations were given to industry professionals to achieve better project success based on the rankings received.

Data Characteristics
The questionnaire was designed using an online tool to help organize, distribute, collect responses, and categorize the collected data. The data were collected from construction professionals worldwide with the help of the website SurveyMonkey. The emails of the respondents were gathered from the network of the research team and the literature review. The questionnaire was sent to 250 participants. 201 responses were received. Only 148 respondents fully completed the survey, and these fully completed responses were considered for analysis. Owners make up 52% of the responses with 77 respondents. Contractors, supervision consultants, and Project Management Consultants (PMC) make up 19%, 18%, and 9% of the responses, respectively and 85% of the respondents work with an organization that has more than 300 employees, whereas only 9% of the respondents work with an organization that has less than 100 employees. Most of the responses come from project management team members, 61% (91 responses). Moreover, 19% and 11% of the respondents are from design/engineering and project control departments, respectively. The rest of the data were from finance and contracts departments. Participants who are project managers make up 41%. Site engineers and operational/general managers make up 11% and 8% of the data, respectively.

Data Analysis
The main goal for all stakeholders in any construction project is to effectively complete the project. This paper mainly aims at defining, examining, and evaluating the CSFs that can affect the performance of any project. The list of 40 factors was established in the same area by analyzing the A total of 148 complete surveys were collected. Relative importance index and Analytical Hierarchy Process were used as statistical tools to rank CSFs. Recommendations were given to industry professionals to achieve better project success based on the rankings received.

Data Characteristics
The questionnaire was designed using an online tool to help organize, distribute, collect responses, and categorize the collected data. The data were collected from construction professionals worldwide with the help of the website SurveyMonkey. The emails of the respondents were gathered from the network of the research team and the literature review. The questionnaire was sent to 250 participants. 201 responses were received. Only 148 respondents fully completed the survey, and these fully completed responses were considered for analysis. Owners make up 52% of the responses with 77 respondents. Contractors, supervision consultants, and Project Management Consultants (PMC) make up 19%, 18%, and 9% of the responses, respectively and 85% of the respondents work with an organization that has more than 300 employees, whereas only 9% of the respondents work with an organization that has less than 100 employees. Most of the responses come from project management team members, 61% (91 responses). Moreover, 19% and 11% of the respondents are from design/engineering and project control departments, respectively. The rest of the data were from finance and contracts departments. Participants who are project managers make up 41%. Site engineers and operational/general managers make up 11% and 8% of the data, respectively.

Data Analysis
The main goal for all stakeholders in any construction project is to effectively complete the project. This paper mainly aims at defining, examining, and evaluating the CSFs that can affect the performance of any project. The list of 40 factors was established in the same area by analyzing the literature of relevant articles, cases, and studies. The evaluation was carried out through a survey filled out by experts from the construction industry. The questionnaire asked participants to define the effect of each factor on performance of a project on the basis of a 9-point scale. The effect of each factor on project performance was asked to be determined by the experts from the construction industry. After collection of data from construction industry professionals, RII and AHP were carried out, respectively. The outputs of these analyses are presented in the coming sections.

Relative Importance Index (RII)
Researchers used the RII to rate factors [16,65,66]. The RII is shown as: Where: W: the weight given to each attribute by the respondents differs between 1 and 9 A: the maximum weight (nine for this study) N: the total number of participants As example, the RII value for the 1st factor, which is project location, was calculated as follows: Table 2. below shows RII values calculated based on the responses from the industry professionals. From Table 2, it can be observed that the top most significant CSFs according to RII are: (1) Decision-making effectiveness (project-management-related); (2) Project's adequate funds/resources (project-related); (3) Top management support (project-management-related); (4) Availability of experienced managers and skillful workforce (contractor-related); (5) Coordination between all participants (project-manager-related).

AHP Analysis
AHP's first step was to establish a hierarchical structure for the analysis. The hierarchical structure can be seen in Figure 2. The first level are the CSFs in the study. The second level includes seven categories as listed earlier.   The next step in AHP was to produce matrices of comparison on a pair basis that are a very important part of the AHP research. The data collected include levels provided to each factor by each Sustainability 2020, 12,1990 8 of 17 participant based on the literature's suggested 9-point scale. Then, for use in a pair-wise comparison procedure, the average values were determined.
To determine the commitment of each organization to the success of the project, a pair-wise matrix was developed. The data collected include levels provided to each factor by each participant based on the literature's suggested 9-point scale (Table 3). Then, for use in a pair-wise comparison, the average values were determined. The next step was to divide each value in every column by the total sum of each column to find the normalized weight. Consequently, average value of each row was calculated and this value becomes the priority weight. Normalized weights and priority weights are shown in Table 4. The consistency ratio for the pairwise comparison was also compared and calculated to be 0.03. This value is less than 0.1 and is acceptable.
The subsequent move is to replicate the same between seven groups and each success factor listed under each of the seven groups. This requires developing many matrices. As a sample, Tables 5 and 6 list normalized weights and priority weights matrices for owner and project-related factors for the owner for illustrative purposes.  Where: PRF, BRF, CLRF, PMRF, DTRF, CORF, PMRF and PW are project=related factors, businessand work-environment-related factors, client-related factors, project-management-related factors, design-team-related factors, contractor-related factors and project-manager-related factors and priority weight, respectively.
The cumulative weight of each performance metric was calculated by multiplying the corresponding weight of each criteria (this weight is calculated for each organization separately. As a sample, the calculation for owner is shown in Table 6) within its organization and the weight of each organization type. This will lead to the finalized AHP weights for each CSF as listed in Table 7.

Discussion of Results and Recommendations to Industry Based on Results
Based on the participants' responses, variables were rated using AHP. The overall score for each factor is presented in Table 7. Further detail for each criteria for the AHP review will be discussed in the section below for the list of top five variables. Figures 3-7

Discussion of Results and Recommendations to Industry Based on Results
Based on the participants' responses, variables were rated using AHP. The overall score for each factor is presented in Table 7. Further detail for each criteria for the AHP review will be discussed in the section below for the list of top five variables. Figures 3-7 below show the most significant CSFs for client, PMC, supervision consultant, design consultant and contractor, respectively. It is found that the most significant CSF is based on the influence of the owner with a score of 0.76. This is anticipated as the client being the largest player in the project. The statutory approval environment (0.66) is the second most important element. The availability of experienced managers and skilled workforce became the third most significant factor. The project's adequate It is found that the most significant CSF is based on the influence of the owner with a score of 0.76. This is anticipated as the client being the largest player in the project. The statutory approval environment (0.66) is the second most important element. The availability of experienced managers and skilled workforce became the third most significant factor. The project's adequate funds/resources and design errors/mistakes are considered as the next significant, with scores of, respectively, 0.41 and 0.39.
At the planning stage, the owner should use a very professional designer. This will ensure accurate project cost estimates and minimal design errors and/or changes. Moreover, a complex framework to promote the issuance of appropriate approvals is recommended for the relevant governmental authorities. This can be achieved by good interagency cooperation. funds/resources and design errors/mistakes are considered as the next significant, with scores of, respectively, 0.41 and 0.39. At the planning stage, the owner should use a very professional designer. This will ensure accurate project cost estimates and minimal design errors and/or changes. Moreover, a complex framework to promote the issuance of appropriate approvals is recommended for the relevant governmental authorities. This can be achieved by good interagency cooperation. As design consultants, the findings of the ranking indicate that the main concerns of the designers were about the sufficient funding/resources of the project besides the legislative approvals. Such two variables, respectively, had ratings of 0.76 and 0.57. The third, fourth, and fifth critical factors include the competence of project managers (0.445), top management support (0.419), and project manager experience (0.391). The designers found that one of the significant CSFs was the top management support. In order to increase efficiency and motivation, top management must provide additional resources to their employees. In addition, training support will improve the design team's performance. The highest scored factor for the supervision consultants is the top management support (0.701). During the construction phase, the supervision consultant needs full support to make the necessary decisions. Consequently, project adequate funds (0.544) is the second important factor. The  As design consultants, the findings of the ranking indicate that the main concerns of the designers were about the sufficient funding/resources of the project besides the legislative approvals. Such two variables, respectively, had ratings of 0.76 and 0.57. The third, fourth, and fifth critical factors include the competence of project managers (0.445), top management support (0.419), and project manager experience (0.391). The designers found that one of the significant CSFs was the top management support. In order to increase efficiency and motivation, top management must provide additional resources to their employees. In addition, training support will improve the design team's performance. funds/resources and design errors/mistakes are considered as the next significant, with scores of, respectively, 0.41 and 0.39. At the planning stage, the owner should use a very professional designer. This will ensure accurate project cost estimates and minimal design errors and/or changes. Moreover, a complex framework to promote the issuance of appropriate approvals is recommended for the relevant governmental authorities. This can be achieved by good interagency cooperation. As design consultants, the findings of the ranking indicate that the main concerns of the designers were about the sufficient funding/resources of the project besides the legislative approvals. Such two variables, respectively, had ratings of 0.76 and 0.57. The third, fourth, and fifth critical factors include the competence of project managers (0.445), top management support (0.419), and project manager experience (0.391). The designers found that one of the significant CSFs was the top management support. In order to increase efficiency and motivation, top management must provide additional resources to their employees. In addition, training support will improve the design team's performance.   The highest scored factor for the supervision consultants is the top management support (0.701). During the construction phase, the supervision consultant needs full support to make the necessary decisions. Consequently, project adequate funds (0.544) is the second important factor. The consultant assumed in the third position that reducing design error/errors would impact project performance (0.533). The remaining two variables are project manager skills (0.5) and project manager's experience (0.413). The PMC considered the project's adequate funds, top management support, and the design team's contribution to construction to be the most significant factors with scores of 0.658, 0.557, and 0.47, respectively. Notwithstanding these reasons, the PMC claimed that in project performance the successful quality assurance system is very critical (0.456). The fifth critical factor with a score of 0.4 is the clear and realistic goals/objectives. This aspect ensures that modifications, disagreements, and disputes are reduced during project lifetime.
Most of the PMC's CSFs have to do with project funds, top management funding, and design team involvement. The quality assurance program was also considered by the PMC to be one of the critical factors. Such standards include project documentation for management of material, production, and workforce.
The top two important factors, according to the contractor's responses in Figure 6, are top management support (0.701) and client/client representative influence (0.606).  The PMC considered the project's adequate funds, top management support, and the design team's contribution to construction to be the most significant factors with scores of 0.658, 0.557, and 0.47, respectively. Notwithstanding these reasons, the PMC claimed that in project performance the successful quality assurance system is very critical (0.456). The fifth critical factor with a score of 0.4 is the clear and realistic goals/objectives. This aspect ensures that modifications, disagreements, and disputes are reduced during project lifetime.
Most of the PMC's CSFs have to do with project funds, top management funding, and design team involvement. The quality assurance program was also considered by the PMC to be one of the critical factors. Such standards include project documentation for management of material, production, and workforce.
The top two important factors, according to the contractor's responses in Figure 6, are top management support (0.701) and client/client representative influence (0.606).
Respondents stressed that the process for organizing, tracking, and managing is a significant factor (0.594). The last two most important factors are, respectively, clear and realistic goals/objectives (0.401) and the commitment of the design team to construction (0.399). The clear and practical goals/objectives were identified as being a top CSF for contractors. Changes in construction projects is one of the causes of failure for any project. For disputes mitigation, the client must devote sufficient time for planning before construction. Contractors are also advised during the bid to carefully review the specifics of the project documents. This study categorized project success factors into categories and quantified the effect of each category on project performance and success considering all project stakeholders. This study differs from others by quantifying the effect of project stakeholders on project success.
Most of the PMC's CSFs have to do with project funds, top management funding, and design team involvement. The quality assurance program was also considered by the PMC to be one of the critical factors. Such standards include project documentation for management of material, production, and workforce.
The top two important factors, according to the contractor's responses in Figure 6, are top management support (0.701) and client/client representative influence (0.606).

Conclusions
This paper aimed at assessing and prioritizing CSFs in the construction industry. A list of 40 CSFs was generated by reviewing literature and related studies to achieve this aim. Under seven major groups, the variables were grouped. Construction industry professionals evaluated the impact level of each factor through a questionnaire. From 148 different construction experts from various types of organizations, responses were received. Employing the Relative Importance Index (RII) and traditional Analytic Hierarchy Process (AHP) method with Saaty random index, the CSFs were prioritized according to seven categories, namely, project-related factors, company-and work-related factors, client-related factors, project-management-related factors, design-team-related factors, contractor-related factors, project-manager-related factors, taking into account the effect of all stakeholders on project efficiency and progress.
The results indicate that the majority of the significant factors were about financial problems (Mechanism of financial payments, project's adequate funds/resources), administrative aspects (Influence of client/client's representative, availability of experienced managers and skillful workforce), and the authorities' approval mechanisms (statutory approvals environment).

Recommendations for Future Study
Combining two or more multiple-criteria decision-making or other methods (i.e., fuzzy AHP, etc.) for validation and ranking of alternatives will gain more robust results.

Data Availability
Data and models generated or used during the study are available from the corresponding author by request.