Study: Cost-Benefit Analyses Are 'Worse Than Worthless'

摘要

A large new global study of project performance over 86 years confirms that ingrained optimism bias results in forecast-based analyses of costs and benefits "so misleading as to be worse than worthless," say U.K. researchers. Study authors from the University of Oxford's Said Business School say cost-benefit theory and practice, developed long before the emergence of behavioral science, "have yet to adapt to its findings about the nature and causes of bias. As a result, the researchers say benefit-cost ratios for various project types continue to be overestimated by between 50% and 200%. To improve project assessment, they call for de-biasing by systematic reference to actual performance of previous projects, incentivizing forecasters for accuracy with rewards and punishments and completing independent audits.