Research and analysis

Rail infrastructure optimism bias study

Investigates the phenomenon of optimism bias in UK rail infrastructure projects.

• From: Department for Transport
• Published: 24 January 2017

Documents

Rail infrastructure optimism bias study: cover note

PDF, 116 KB, 1 page

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Optimism bias study: recommended adjustments to optimism bias uplifts

PDF, 2.68 MB, 39 pages

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Details

Optimism bias is the tendency of individuals to expect better than average outcomes from their actions. In the context of rail infrastructure projects, optimism bias can lead to:

• underestimation of project duration
• overestimation of benefits
• underestimation of total cost

This study looks at evidence from rail infrastructure projects and recommends how the optimism bias uplift values should be changed.

Published 24 January 2017