Which attributes define a megaproject?

Megaprojects are highly complex undertakings that significantly impact the world. Flyvbjerg states megaprojects require significant resources: “Over Budget, Over Time, Over and Over Again.” Megaprojects impact society decades after they are delivered, and a higher success rate is crucial, especially in light of sustainability. The number of megaprojects is increasing, the complexity of the projects is unique, and ownership is becoming increasingly complex. This research discusses how megaprojects are defined according to existing literature. What do we consider a megaproject? Furthermore, which attributes (complexity, stakeholder management, project ownership, and so on) can be used as an Early Signal to identify which delivery model is needed? With a premise that a megaproject needs to be handled differently than a conventional project. This paper is based on a literature review examining the definition of megaproject. The literature review shows that megaprojects are typically defined as a delivery model to deliver large-scale, complex, and one-off capital investments in the public and private sectors. Or a project system greater than 0.01% of the national gross domestic product (GDP). Our results show that there are no common definitions of what a megaproject is in the literature. Our research shows that a higher focus on complexity, technology, novelty, duration, stakeholder management, project governance, and political ramifications is more critical in defining a megaproject than the project’s capital cost or size (tonn, m2, or length).