Bent Flyvbjerg

Born in Denmark in 1952, professor of major programme management at the University of Oxford and professor at the IT University of Copenhagen, Flyvbjerg made his name with Rationality and Power (1998), a study of the Aalborg traffic plan that showed, meeting by meeting, how the interests of shopkeepers and the police hollowed out a rational plan until it became the opposite of what it intended. His conclusion, that power defines what counts as rational, is one of the most cited texts in planning theory.

Megaprojects and Risk (2003) opened his second line: the world's largest database on major projects, more than sixteen thousand, shows that nine out of ten go over budget, that overruns have not improved in seventy years and that the cause is not bad luck but optimism bias and the strategic misrepresentation of those who need the project approved. He proposed reference class forecasting, which the United Kingdom and Denmark adopted.

How Big Things Get Done (2023), with Dan Gardner, summed up that evidence for a wide public: think slow and act fast, modularise, learn from similar projects. He also defended case-based social science in Making Social Science Matter (2001). He is the reference for evaluating Olympic Games, high-speed rail and metro lines.