What You Should Know About Megaprojects, and Why
TL;DR — Why big projects overrun, by the researcher who assembled the dataset — nine out of ten go over budget, and the reasons are structural.
⬇ Download the archived copy — kept here so the document survives its source going dark. arXiv preprint (author distribution licence).
An overview of the megaproject literature by the person who built its empirical base.
Flyvbjerg’s core finding is that cost overrun and benefit shortfall are not random noise but systematic: roughly nine in ten megaprojects exceed budget, the distribution of overruns is fat-tailed, and the pattern has not improved over decades of study.
The explanation has two parts that are usually confused. Optimism bias is a cognitive error. Strategic misrepresentation is a deliberate one — forecasts are shaded because a project that looks expensive does not get approved, so the projects that get built are selected for having the most misleading forecasts.
His remedy is reference-class forecasting: ignore the plan, look at what comparable projects actually cost. Directly load-bearing for City Building.
Where this came from
30 pages. A copy is archived locally against link rot; the header links the original source.