Reform and modernisation of the construction sector are ongoing concerns to governments in numerous countries, due to the low rate of innovation and productivity in the sector. Policy interventions, particularly those associated with digital technologies, are being used to promote innovation and transformation of the sector. Digitising building information through building information modelling (BIM), for example, has been claimed to be transformative and has been mandated by governments in multiple countries. Institutional theorists would describe this as coercive isomorphism – encouraging firms across sectors to adopt the same practices. In the UK and many other countries, formal structures have been devised and imposed as part of these coercive efforts, including standardised processes for managing information on delivery, handover and throughout operation. However, evidence suggests that these coercive pressures and the national BIM approaches have not produced the envisaged systemic change at the pace expected by institutional designers. The academic literature has also acknowledged that industry-wide implementation of BIM has progressed slowly despite constant claims that BIM is a vehicle for realising radical, transformational change in the construction industry. In reality, organisations and projects are not necessarily passive receptors of imposed policies; yet the project management and construction management literatures offer limited understanding of the effects ‘within’ projects when institutional pressures are applied. In the case of BIM, there is a shared and implicit assumption that a multitude of stakeholders will readily accept the BIM discourse and the prescriptions that follow it. This thesis challenges such assumptions, arguing that the adoption and implementation of BIM through institutional pressure will not be straightforward. Project management scholars have cited a low level of concern for the internal processes of projects and how they interact with broader institutional issues as a major weakness of current theorising in project management in connection with actual practice. Thus, this research takes the perspective of projects as implementers of institutional pressures to explore how this interaction unfolds. Specifically, it examines the case of the BIM level 2 mandate in the UK, which is considered a mature country in terms of BIM adoption, as well as the BIM policy approach as an example of an institutional (coercive) pressure. Based on insights from institutional and structuration theories, and through inductive and longitudinal case studies of eight projects from three settings with varying motivations for implementing the BIM level 2 mandate, this research identifies and conceptualises how projects might respond to an institutional pressure and the predictors of such responses. The findings reveal that hybrid responses can emerge when projects are faced with institutional pressures to impose a new structure, which are underlined by both coupling and decoupling from the imposed structure. Decoupling occurs in two main forms: decoupling from the ‘what’, or the content of the imposed structure; and/or decoupling from the ‘how’ of the imposed structure, or its implicit meaning. The rationale underlying coupling and decoupling responses involves both the willingness and the ability of projects to respond to the institutional environment. The findings also evidence that decoupling in projects takes place under conditions of complex causality and presents characteristics of conjunction and equifinality. These insights demonstrate that combinations of multilevel institutionalised structures and organisation-level variables shape how projects respond to environmental pressures. By exploring how projects interact with institutional pressures and conceptualising decoupling in the context of projects, this research contributes to several streams of literature. First, it extends the current conceptualisation of policy-practice decoupling in the organisational theory literature by proposing a more fine-grained conceptualisation wherein decoupling occurs not only under the conditions of a lack of holistic adoption and/or implementation of structures or its content (the ‘what’) but also when the implicit meaning (the ‘how’) of the structure is not enacted. The findings further elaborate on the role of the imposed structure itself and a prior decoupling that might take place at the level of the imposed structure, which stresses the impact of the imposed rules on the mechanisms that lead to decoupling at the ground level. Second, from the project management and construction management perspectives, this study directly addresses recent calls for more research that theorises the interactions of projects with the wider environment through the lens of management theories, such as institutional theory. The findings suggest that the process of change and institutionalisation of new structures imposed by the environment is a process of structuration, influenced by structures from the multiple contexts in which projects are embedded. Finally, from a BIM perspective, this study enriches debates that challenge perceptions of BIM enactment as a linear process of implementation. Although the existing literature has already identified a range of factors that affect BIM adoption and implementation, this research highlights the combined influence of multiple factors within various project contexts on ‘how’ the implementation of a BIM mandate actually proceeds at the ground level.