The Delphi Method: Review and Use in Construction Management Research

Developing a novel energy-based approach for measuring mental workload

Minimal research has been conducted to develop non-invasive processes for quantifying and evaluating worker mental workload - a critical concern - at the task level in the construction industry. One reason for this gap in research is the complex and dynamic nature of the construction process, which makes construction work more complicated to measure and predict compared to work in other industries. This paper presents a novel approach and corresponding conceptual model to quantify and evaluate construction worker perception of mental workload at the task level using the energy concept. A conceptual process for assessing mental workload (MWL), i.e., the feeling of stress, pressure, and being overwhelmed due to the task nature, factors, conditions, and resources that accompany the performance of the task, was developed from extant research and interviews. The Delphi method was utilized to characterize the energy-based model and provide initial verification. The results from the literature review, expert insight, and four rounds of the Delphi survey revealed 14 constituents, 51 components, and one metric for each component to measure the level of MWL felt by a worker. These constituents, components, and metrics were used to develop a model for measuring construction worker MWL. This study contributes to knowledge by developing a novel non-invasive method for assessing potential task-level MWL using an energy-based model. The energy-based assessment model contributes to practice by providing a tool that could be used to measure the potential impact of construction tasks on workers perceived mental workload.

Circular economy strategies for waste management in Sri Lanka: A focus on demolitions and repurpose and material recovery and production stages

In Sri Lanka, the management of Construction & Demolition (C&D) waste poses a major problem, leading to environmental degradation and depletion of resources. This study aims to tackle these issues by examining the implementation of Circular Economy (CE) strategies within the construction industry of Sri Lanka. The focus is on reducing waste generation and maximizing resource utilization during the demolitions and repurpose, as well as material recovery and production stages of the building project life cycle. These stages are crucial in terms of waste generation and resource consumption. A qualitative approach was employed in this research, utilizing the Delphi technique to gather insights through a series of three rounds of expert interviews. In the first round, 17 experts were involved, followed by 15 in the second round, and 12 in the final round. The data collected from these interviews were analysed using manual content analysis methods. Based on the research findings, a total of 14 C&D Waste Management (WM) issues were identified specifically in the Demolitions and Repurpose Stage in Sri Lanka. For each issue, suitable strategies were proposed to overcome them effectively. Furthermore, the study examined the impact of CE strategies on minimizing these issues within the context of the project management iron triangle. Similarly, the Material Recovery and Production Stage of the building presented eight C&D WM issues, each accompanied by corresponding strategies to address them. The research also explored the influence of CE strategies in mitigating these issues, considering the project management iron triangle. During the demolitions and repurpose stage, CE strategies focus on reducing waste generation and optimizing resource utilization. This involves carefully deconstructing buildings to salvage and recover materials that can be reused or repurposed.

Evaluating quality management of road construction projects: a Delphi study

Purpose

There are various methods to assess the failure of a road construction project that does not meet quality and performance standards. This study aims to evaluate the factors affecting the quality management of road construction projects in Indonesia by identifying the critical challenges in implementing quality management processes and examining the countermeasures to address these problems.

Design/methodology/approach

In this research, the quality management processes in Indonesian road construction projects are evaluated using a mixed quantitative and qualitative approach. Quantitative data obtained from two rounds of Delphi questionnaire surveys as the primary data source, and focus group interviews as the qualitative data are used to achieve the aims of this study.

Findings

It is found that from as early as in the preconstruction stage of a project, the availability of quality standards and documentation is problematic when implementing quality management processes. The critical factor of the quality control activities of a project and the quality management roles and responsibilities of the stakeholders during road construction is the project team. This constraint deals with the interaction of the competency, commitment, and mutual cooperation among the main stakeholders to ensure that quality management processes are implemented. This implementation is a part of controlling the road pavement materials, supervising the project activities according to a specified standard, and reporting the project performance. The findings of this study add parameters relating to quality management and quality processes in a road construction project area.

Originality/value

This study is the first to evaluate the quality management processes in the construction of Indonesian road projects. The investigation identifies and evaluates the causes of the persistence of poor road quality. All revealed constraints are substantial factors that hinder the implementation of quality management processes when delivering quality road products. This study addresses the key influencing factors and scenarios related to quality management during road construction projects in Indonesia and other developing countries as practical examples and provides case-based insights for construction practitioners and civil engineering academics in developed countries.

Challenging Tendering-Phase Factors in Public Construction Projects—A Delphi Study in Saudi Arabia

Public construction projects in Saudi Arabia are fraught with several challenges threatening open and fair competition, which consequently negatively influence the decision of contractors to participate in bidding. Nevertheless, the construction sector has witnessed rapid reforms since 2016, which have resulted in the issuing of new legislation and regulations as well as the creation of governing bodies. Hence, the concept of open and fair competition plays a significant role in the governance of these challenges in the upstream process of construction tendering. Therefore, this paper explores challenges that are hindering contractors’ participation in the tendering phase of public construction projects in light of these new legislations and authorities. Twelve challenging factors were identified from a structured literature review of previous relevant empirical studies available in online search engines since the 1980s. Those factors were measured through Delphi survey questionnaires, which provided respondents with the option of adding new challenging factors. Thus, twenty factors were identified. A descriptive method was used to determine and prioritize these challenging factors. The survey findings indicate that the most influential hindering factors are (1) awarding contracts based on the lowest bidder, (2) inadequate or incomplete specifications, (3) poor contract documents, and (4) poor cost-estimating practices. These findings are vital in exposing the lack of relationships between the construction industry, regulators, and stakeholders for robust partnerships, thereby helping to ensure the fair participation of contractors, which boosts open and fair competition concepts for public construction projects.

An Empirical Study on Data Validation Methods of Delphi and General Consensus

Data collection and review are the building blocks of academic research regardless of the discipline. The gathered and reviewed data, however, need to be validated in order to obtain accurate information. The Delphi consensus is known as a method for validating the data. However, several studies have shown that this method is time-consuming and requires a number of rounds to complete. Until now, there has been no clear evidence that validating data by a Delphi consensus is more significant than by a general consensus. In this regard, if data validation between both methods are not significantly different, then just using a general consensus method is sufficient, easier, and less time-consuming. Hence, this study aims to find out whether or not data validation by a Delphi consensus method is more significant than by a general consensus method. This study firstly collected and reviewed the data of sustainable building criteria, secondly validated these data by applying each consensus method, and finally made a comparison between both consensus methods. The results showed that seventeen of the valid criteria obtained from the general consensus and reduced by the Delphi consensus were found to be inconsistent for sustainable building assessments in Cambodia. Therefore, this study concludes that using the Delphi consensus method is more significant in validating the gathered and reviewed data. This experiment contributes to the selection and application of consensus methods in validating data, information, or criteria, especially in engineering fields.

Improving Risk Assessment for Transporting Dangerous Goods through European Road Tunnels: A Delphi Study

Managing the transportation of dangerous goods (DG) through road tunnels is of great importance since it is associated with a serious risk of accidents. The consequences of an accident involving DG, especially in the closed tunnel environment, might be more significant and even more catastrophic compared to the same accident occurring on an open road. This article presents the Greek experience regarding the application of quantitative risk assessment (QRA) methods for the transportation of DG through Greek road tunnels. The modified Delphi method, with the participation of nine experts, is employed to investigate the obstacles to successfully conforming with the mandatory European Union regulatory framework that applies to transport operations within the Trans-European road network. Recommendations are made to improve the applied QRA approach, to facilitate the cooperation between tunnel managers and emergency services, to communicate lessons learned and to enhance the training of risk assessors.

Constructing an Evaluation Index System for China’s Low-Carbon Tourism Region—An Example from the Daxinganling Region

With the intensification of global warming, the development of low-carbon tourism is not only an inevitable requirement for human development, but also an important way to enhance tourism, improve the quality of tourism, and obtain greater economic and social benefits from tourism. Scientifically and effectively constructing a low-carbon tourism development level evaluation index system is conducive to the healthy and sustainable development of the tourism industry. However, the current evaluation of the development level of low-carbon tourism mainly focuses on low-carbon development, energy conservation, and emission reduction. There are few studies and a lack of specific empirical research evaluating the development of low-carbon tourism. In this research, the Delphi method and analytic hierarchy process were used for data collection and corresponding weight analysis. This research refers to the results of existing studies on low-carbon tourism evaluation index systems, and constructs an objective and quantitative evaluation model. It establishes a low-carbon tourism development evaluation model with 34 specific indicators from the three dimensions of the tourism economic support level, the tourism low-carbon development level, and the tourism policy support level. The research results were applied to the Daxinganling region for verification. The results show that the development of tourism in the Daxinganling region has changed from a mode dominated by economic interests to a mode in which tourism-related parties begin to seek effective low-carbon methods to maintain low-carbon tourism activities. In addition, the Daxinganling region has the lowest level of low-carbon tourism development and the highest level of financial support. Based on the research conclusions, corresponding suggestions for the development of low-carbon tourism in the Daxinganling region are provided. The results are also intended to provide a reference point in the optimization of low-carbon tourism development models in this and other regions.

Mediterranean Diet conceptual model and future trends of its use in Portugal

The aim of this study was to present a new model for the Mediterranean Diet definition and to identify the major trends for the use of the Mediterranean Diet concept by 2028, in Portugal. A Delphi panel was implemented with 28 experts with solid knowledge and understanding of the Mediterranean Diet concept. The first round evaluated the degree of expert self-knowledge, which also contributed to the final questionnaire building. It was answered in 2 successive rounds with 21 statements, divided into 2 dimensions: Mediterranean Diet concept and use. A Mediterranean Diet model definition was produced with 73.8% of agreement. Culture, education, environment, health, food industry/distribution and tourism were identified as the future trends of Mediterranean Diet use areas. The model presented can be used as a pedagogical tool. For the first time, it was possible to explore the future trends of Mediterranean Diet use, which can help with the initiatives to safeguard the Mediterranean Diet concept.

Optimizing safety-measure combinations to address construction risks

Objectives. Most methods used to develop construction risk responses address the risk-mitigation optimization problem by solving the objective functions. They are passively achieved by satisfying constraint conditions, which are not adequate for efficient construction management. This study aims to provide an active optimization strategy for selecting risk responses. Methods. We combined set pair analysis (SPA) with the technique for order preference by similarity to an ideal solution (TOPSIS) to control the construction risks to an acceptable level instead of excessively to the minimum level. SPA is employed to assess the pre-mitigation and post-mitigation risk levels based on the uncertainty theory, and the TOPSIS is used to rank safety measures based on their risk-mitigation effects. A case study of concrete pumping for a super high-rise building was used to exemplify how the proposed optimization model assists risk control and to validate its reasonability. Conclusion. The developed TOPSIS-SPA-based method figures out the optimal safety-measure combination reducing construction risks economically to an acceptable level with the fewest number of measures. The findings can assist decision-makers in formulating cost-effective risk-control schemes.

Home-Delivery-Oriented Agri-Food Supply Chain Alliance: Framework, Management Strategies, and Cooperation Stability Control

The high cost of operation and severe competition in the agri-food e-commerce market make it hard for the small and medium agri-food enterprises (A-SMEs) to operate cost-efficiently and in a sustainable manner. This paper seeks to organize A-SMEs to develop a cooperative organization via collaborative strategies and alliance structures, named as the home-delivery-oriented agri-food supply chain (HASC) alliance, to form a substantive relationship to gain a stable foothold in the emerging e-commerce market. A theoretical framework of the HASC alliance is built with its organizational structure and schematics of the process of implementation strategies that cover the aspects of last-mile chain extension, food transportation, and production/distribution control. Furthermore, a three-step analytical method is proposed to analyze the performance of the alliance with the aim to provide appropriate strategies to hedge against the potential risks of cooperation instability. A hypothetical case is conducted, and the results show that: (1) the performance of the hypothetical HASC alliance with time shows significant variation in the beginning, but it gains stability with the application of stability control strategies; (2) the cooperation stability of HASC alliance is very sensitive to the performance of the strategies that control the customer and environment variations; (3) the factors of trust and market fluctuation have higher effects on membership and environmental stability, respectively; (4) the minimum and maximum cost ranges of control strategies at which the alliance can maintain its stability and performance are 5% and 29%, respectively, of the total operation cost.

Development of Sustainability Indicators for Employee-Activity Based Production Process Using Fuzzy Delphi Method

Production process sustainability refers to a manufacturing system in which manufacturing industries produce products in a sustainable way. In recent years, sustainability has become a major concern and challenge for manufacturing systems because of growing consciousness of the effects of their activities on the environment, society, and economy. Different organizational reports and the academic literature have proposed indicators of sustainable manufacturing that help to measure product and process sustainability. However, little of the previous research is related to employee-activity based indicators for production process sustainability. To bridge the gap, this study identified a set of indicators of production process sustainability based on direct and indirect impacts of manufacturing activities on employees, who are key resources in the entire production process, for efficiently applying a sustainability perspective. In addition, the paper provides an evaluation model for selecting relatively important indicators based on expert opinions. A fuzzy Delphi method was applied for the screening process of the decision makers (experts). A Delphi questionnaire prepared with a nine-point linguistic scale corresponding to respective linguistic variables was utilized to assess expert opinions on the importance of each indicator. These expert opinions were aggregated for each indicator by using an adopted algorithm that considers the degree of importance allocated to the decision makers, and the similarity and distance among decision maker opinions. Lastly, the key employee-activity based indicators were chosen based on the threshold value set.

A Hybrid Weight Assignment Model for Urban Underground Space Resources Evaluation Integrated with the Weight of Time Dimension

The utilization of urban underground space resources (UUSR) are important approaches to effectively save land resources, improve the living environment, expand the urban space, and achieve sustainable urban development. To obtain accurate UUSR evaluation results, the weight assignment of indicators plays an important role in the evaluation process and is an indispensable part of it. Reasonable weights of indicators can greatly improve the accuracy of the final UUSR evaluation results. Neither the basic characteristics of cross-section data and time series data of UUSR evaluation indicators are taken into consideration simultaneously, nor is the combination and cross application of different weighting methods in the previous weight assignment of UUSR evaluation indicators. Considering the influence of the time dimension, the weighting method of time dimension is introduced into the UUSR evaluation. Through integrating the classical entropy weight method, which is a frequently-used weighting method of indicator dimension with the weighting method of time dimension in two different approaches by time ordered weighted averaging (TOWA) operator, the hybrid weight assignment model named entropy and time weighting model (E-TW) for UUSR evaluation is proposed. The experimental calculation results show that the UUSR evaluation results using the E-TW model are significantly better than the results using the single classical entropy weight method, which means the hybrid weight assignment model is more suitable for UUSR evaluation than the single weighting method of indicator dimension.

Digital local information services in developing countries: Evidence from Colombia

This exploratory research identifies and investigates factors that affect the delivery of local information in a developing country. The service provider and 195 local institutions based in Medellin, Colombia collaborate through an online portal, Infolocal, constituting a local information landscape (LIL). The study implements a conceptual framework for the LIL and highlights deficiencies in traditional local information service models. A Delphi study was conducted with global experts of local information services (LIS) in order to refine the traditional Unified Theory of Acceptance and Use of Technology model constructs for the Infolocal information service. Second, a survey was developed based on the revised categories (effort expectancy, performance expectancy, social influence, facilitating conditions, organisational support, and affective commitment) and disseminated to the local institutions to assess their perceptions of the service. This data was then evaluated using exploratory factor analysis. The study found that theories of technology acceptance were insufficient in explaining the disjunctions in the information landscape of this service. This study contributes to closing a gap in understanding the perceptions of LIS practice from the perspective of institutions that engage directly with citizens’ technology acceptance and use behaviour in a multilevel relationship. This article captures, compares, and analyses the disjunctions between the theoretical frameworks as espoused by experts and the practices of LIS.

Prioritizing Sustainable City Indicators for Cambodia

This research is based on our previous research that developed consensus sustainable city indicators for Cambodia through three-round Delphi panel surveys. That research developed indicators in the first round based on UN sustainable development goal 11, ASEAN environmentally sustainable city, Korean case study, and domestic green and clean city indicators, and validated the developed indicators in the last two rounds. After consensus analysis, that research obtained 32 assessment indicators categorized by nine criteria. However, these indicators are not prioritized yet due to the limitation of the Delphi technique. Hence, this research aims to prioritize these indicators by applying the Analytic Hierarchy Process (AHP) technique and to confirm whether the levels of importance verified by Delphi can be used for prioritizing or ranking the indicators. This research surveyed potential respondents experienced and working in relevant fields both offline and online. Online surveys were processed through E-mail, Facebook, and LinkedIn. A total of 118 questionnaires were gathered from the surveys, and 16 were inconsistent (consistency ratio > 0.1). The results showed that the highest and lowest weights are 0.0557 and 0.086. The top ten indicators are slum population (0.0557), unemployment (0.0516), crime prevention (0.0470), water supply (0.0469), city’s migration (0.0462), low-income housing (0.0445), solid waste collection (0.0437), labor-force (0.0421), construction safety (0.0400), and traffic congestion (0.0398). The rank of all indicators based on their levels of importance is completely different from the rank of their weights. Therefore, this research confirms that the levels of importance verified by Delphi cannot be used for ranking or prioritizing the consensus indicators. The priority weights in this research would be useful to policymaking, strategic direction, and budget allocation for the development and management of sustainable cities in Cambodia.

A Comprehensive Study of Project Risks in Road Transportation Networks under CPEC

The China–Pakistan economic corridor (CPEC) is a collection of different ongoing projects including transportation, infrastructure, the Gwadar seaport, oil pipeline, and internet connection zone projects. The Chinese government has adopted a development strategy for infrastructure growth and investment in Pakistani and Asian territories through the CPEC project. Transportation is considered the backbone of the CPEC. In addition to the CPEC project is the linked “belt and road initiative” (BRI) project, which aims to enhance regional connectivity and is a harbinger of the future in Asia, as well as in European countries. However, uncertain situations, such as a lack of proper planning, security, and political stability, hinder the growth and development of infrastructure. Three corridors of the CPEC road transportation network, namely, the eastern, the western, and future central alignment, have been examined through a master supposition group using the Delphi technique, which has never been applied to the road transportation network in the CPEC plan. The review is designed to draw master conclusions and demonstrate an outcome for round one and two in the present work. Round one and two investigate the impact of stakeholder support, politicians’ roles, terrorism, security situations, poverty, and economic crises. Using the Delphi technique within the host country hinders the construction of the road network. The results obtained through the appraisal have justified the present potential endeavor.

Developing Sustainable City Indicators for Cambodia through Delphi Processes of Panel Surveys

Currently, Cambodia does not have sustainable city indicators, and green and clean city indicators are also limited compared to UN Sustainable Development Goal 11 (SDG 11) indicators. Therefore, this research aims to develop sustainable city indicators for Cambodia and to address the questions “Are the green and clean city indicators limited in terms of sustainability?” and “Are the UN SDG 11 indicators suitable for Cambodia?” Delphi processes of panel surveys were conducted to develop the indicators in Round 1, pre-validate the indicators in Round 2, and validate the indicators in Round 3. The results showed that 69 initial indicators were obtained from Round 1; 41 pre-validated indicators were obtained from Round 2; and finally, 32 validated indicators were obtained from Round 3. All of the 32 indicators reached consensus. Based on the consensus indicators, the green and clean city indicators were found to be limited in terms of sustainability, and the UN SDG 11 has nine indicators suitable for Cambodia. These findings could be useful for applying the UN SDG 11 indicators to Cambodia and transforming the green and clean city indicators to sustainable city indicators. The 32 consensus indicators could be used as alternative sustainable city indicators for Cambodia.