A Framework for Integrating Sustainability Metrics into Cost Estimation Models

Thesis Abstract

The escalating global emphasis on sustainable development and environmentally responsible construction practices necessitates the integration of sustainability metrics into traditional cost estimation models within the construction industry. Despite the acknowledged importance of sustainability in project evaluation, current cost estimation frameworks largely neglect comprehensive incorporation of environmental, social, and economic sustainability indicators, leading to potential undervaluation of long-term project impacts and suboptimal decision-making. This study aims to develop a robust, contextually adaptable framework for integrating sustainability metrics into conventional cost estimation models, thereby enhancing their capacity to produce more holistic and sustainable project cost forecasts. The primary objectives include (1) review of existing cost estimation methodologies and sustainability assessment tools; (2) identification of relevant sustainability metrics applicable across various construction contexts; (3) formulation of an integrated model that systematically incorporates these metrics into cost estimation processes; and (4) validation of the proposed framework through empirical case studies. To achieve these objectives, a mixed-methods research design was adopted, combining qualitative and quantitative approaches for comprehensive analysis. The qualitative phase involved thematic analysis of semi-structured interviews with 25 construction industry professionals, including quantity surveyors, sustainability consultants, and project managers, to elicit insights on current practices, challenges, and key sustainability indicators. The quantitative phase entailed a descriptive survey administered to a broader sample of 150 industry practitioners to gather data on current estimation practices and perceptions of sustainability integration, complemented by an experimental component applying the proposed framework to five recent construction projects within the metropolitan region. Data collection instruments comprised structured questionnaires, interview guides, and project financial documents. The validity and reliability of the questionnaires were established through pilot testing and Cronbach’s alpha coefficients exceeding 0.85. Data analysis involved thematic coding for qualitative data and advanced statistical techniques, most notably multiple regression analysis and factor analysis, to examine the relationships between sustainability metrics and cost estimations. The analytical framework was supported by theoretical foundations from the Natural Capital Theory and Stakeholder Theory, underpinning the rationale for considering environmental and social factors explicitly in project cost models. It is anticipated that the study will reveal significant correlations between sustainability metrics—such as ecological footprint, social impact scores, and lifecycle costs—and traditional cost elements, underscoring the necessity for an integrated approach. The findings are expected to demonstrate that projects incorporating sustainability considerations can achieve better cost predictability, risk management, and stakeholder satisfaction, ultimately leading to more sustainable building practices. The research contributes to existing knowledge by proposing a novel, adaptable framework that formally embeds sustainability metrics into cost estimation models, providing practitioners with a practical tool for advancing sustainable construction. It extends theoretical understanding by operationalizing sustainability indicators within quantifiable cost analysis, fostering a paradigm shift toward holistic project valuation. The main conclusion advocates for industry-wide adoption of integrated models, emphasizing policy implications and the need for capacity building within the construction sector. Recommendations include the development of software tools based on the framework, industry training programs for sustainability integration, and further empirical testing across diverse project types and geographic regions to refine and generalize the model. Future research should explore the application of the framework in public infrastructure projects and investigate the long-term cost benefits associated with sustainable building practices. Overall, this study aims to facilitate more sustainable project planning and decision-making processes, ultimately contributing to the reduction of construction’s environmental footprint and promotion of social equity within the industry.