an incentive to exaggerate

Too bad the Duluth School Board saw the Red Plan through rose tinted glasses. They should have known better.

On average, urban and intercity rail projects run over budget by 45 percent, roads by 20 percent, and bridges and tunnels by 34 percent. A charitable explanation is that promoters are starry- eyed and suffer from what psychologists call optimism bias. But it’s suspicious that forecasters rarely seem to learn, even over decades of experience. Alas, contractors, local governments and other advocates have strong incentives to underplay costs and exaggerate benefits to sell their services or attract funding.

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