The article by Bent Flyvbjerg, Mette Skamris Holm, and Søren Buhl examines the issue of cost underestimation in public works projects, particularly transportation infrastructure. Using a sample of 258 transportation projects worth $90 billion, the study finds that cost estimates used for decision-making are highly and systematically misleading, leading to significant cost escalation. The authors argue that cost underestimation is not due to error but rather strategic misrepresentation, i.e., lying. The study shows that cost underestimation is common across different project types, geographical regions, and historical periods. The data indicate that actual costs are, on average, 28% higher than estimated costs. Rail projects show the highest underestimation, followed by fixed links and roads. The study also finds that cost underestimation is more pronounced in developing nations. The authors conclude that cost underestimation is a global phenomenon and that it is best explained by deliberate deception rather than errors. The study emphasizes the need for policy changes to ensure more accurate cost estimates and to prevent the misallocation of resources. The authors suggest that institutional checks and balances, including financial, professional, and criminal penalties for estimation errors, should be developed to ensure more accurate cost estimates. The study also highlights the importance of transparency, performance specifications, and the involvement of private risk capital in project development. The authors conclude that cost underestimation is a significant problem in public works projects and that it is best explained by deliberate deception rather than errors. The study calls for further research to better understand the causes of cost underestimation and to develop more accurate cost estimates.The article by Bent Flyvbjerg, Mette Skamris Holm, and Søren Buhl examines the issue of cost underestimation in public works projects, particularly transportation infrastructure. Using a sample of 258 transportation projects worth $90 billion, the study finds that cost estimates used for decision-making are highly and systematically misleading, leading to significant cost escalation. The authors argue that cost underestimation is not due to error but rather strategic misrepresentation, i.e., lying. The study shows that cost underestimation is common across different project types, geographical regions, and historical periods. The data indicate that actual costs are, on average, 28% higher than estimated costs. Rail projects show the highest underestimation, followed by fixed links and roads. The study also finds that cost underestimation is more pronounced in developing nations. The authors conclude that cost underestimation is a global phenomenon and that it is best explained by deliberate deception rather than errors. The study emphasizes the need for policy changes to ensure more accurate cost estimates and to prevent the misallocation of resources. The authors suggest that institutional checks and balances, including financial, professional, and criminal penalties for estimation errors, should be developed to ensure more accurate cost estimates. The study also highlights the importance of transparency, performance specifications, and the involvement of private risk capital in project development. The authors conclude that cost underestimation is a significant problem in public works projects and that it is best explained by deliberate deception rather than errors. The study calls for further research to better understand the causes of cost underestimation and to develop more accurate cost estimates.