Modular construction has been hailed as an innovative construction approach for overcoming labor shortages, the aging workforce, and low productivity in the construction industry. Previous studies focused on the technical aspects, but few contextualized modular construction in sustainable development (SD), nor analyzed stakeholders' knowledge, attitudes, and intentions toward adopting modular construction for SD. This paper develops a three-level knowledge-attitude-intention model to examine stakeholders' knowledge, attitudes, and intentions from technical, economic, social, and environmental aspects. The empirical research was conducted through a questionnaire survey with 197 stakeholders in the Hong Kong construction industry. The results indicate inconsistent knowledge, polarized attitudes, and high intention of stakeholders toward modular construction for SD in Hong Kong. The statistical analysis results show stakeholder differentials lead to differences in stakeholders' knowledge and attitudes about modular construction for SD, but no statistically significant difference was found in behavioral intentions. Besides, knowledge and attitudes were found to be significantly correlated to intention on modular construction for SD. The stakeholder knowledge, attitudes, and intentions toward modular construction for SD were considered to be complex sociotechnical systems, which led to varied articulations of the dialectics and complexities of modular construction for SD. The study contributes to the literature with systems thinking by scrutinizing institution-demand-supply-regulatory collaborations and partnerships, integrating the ontological, axiological, and epistemological understanding of stakeholders, revealing dialectic of stakeholders' knowledge, attitudes and intentions, and reviewing multifaceted and interwoven technical, economic, social, and environmental aspects of modular construction for SD. Practical implications are provided to enable the exchange of knowledge on innovative modular construction for SD with institutions and industry, shape the attitude of industry and society stakeholders toward sustainability, and encourage the practice of innovation-driven SD. Practical applications could be further imposed to enhance the knowledge, shape the attitudes, and encourage the intentions about adopting modular construction for SD in Hong Kong as follows: To enhance the knowledge of modular construction for SD, the understanding of sociotechnical systems of modular construction coupled with economic, social, and environmental sustainability of modular construction is recommended. Industry councils are recommended to publish guidelines on the technical solutions for achieving a sustainable built environment through modular construction. Industry pioneers and practitioners are encouraged to demonstrate and share the feasibility and benefits of applying modular construction for the public and other industry stakeholder groups. Regarding knowledge acquisition-sharing-application mechanism, the relationships between institutions and other stakeholder groups should be enhanced and strengthened by an institution-demand-supply-regulatory partnership. This enhancement would be beneficial for knowledge transfer and able to bridge academic outcomes with industry needs. In terms of attitudes, the government and developers are encouraged to collaborate with universities and professionals to raise awareness of the sustainability of modular construction for SD in urban development. Government departments should formulate more legislation and initiatives to change current unwillingness and negative attitudes toward modular construction for SD, especially social sustainability. Thus, promoting corporate social responsibilities of adopting modular construction for SD through public media should be considered to raise the industry's interests and the general public's awareness. Enhancing stakeholders' intentions should be addressed and emphasized at the current stage to guide and encourage the adoption of modular construction for SD in the future. Engaging a policy mix that includes carrot, cusp, and stick policies is recommended to achieve feasible and effective enhancement toward stakeholders' intentions and practices of modular construction for SD. The policy mix includes carrot policies (tax incentives, rebates, and grants), cusp policies, which are neither clearly carrot nor stick, but often have a leaning toward one or other (loans and improved rental/selling rights), and stick policies (minimum standards and mandatory disclosure).
