  This paper argues, first, that a major problem in the planning of large
infrastructure projects is the high level of misinformation about costs and
benefits that decision makers face in deciding whether to build, and the high
risks such misinformation generates. Second, it explores the causes of
misinformation and risk, mainly in the guise of optimism bias and strategic
misrepresentation. Finally, the paper presents a number of measures aimed at
improving planning and decision making for large infrastructure projects,
including changed incentive structures and better planning methods. Thus the
paper is organized as a simple triptych consisting in problems, causes, and
cures.
