Update Optimism Bias Guidance
Optimism bias guidance, based on decades-old data, requires updating to include light rail projects and reflect current empirical evidence, with reviews every five years.
- No published update to optimism bias guidance incorporating light rail project data or reflecting current empirical evidence has been identified to March 2026.
How was this evidence gathered?
Response
Accepted in Part
Response
Accepted in PartTransport Secretary's Statement to Scottish Parliament, 2 November 2023: "We follow detailed Government guidance on procurement, risk and optimism bias as enshrined in the Treasury's Green Book, the Scottish Government's Client Guide to Construction Projects and the Scottish Public Finance Manual. [...] I emphasise that we will continue to very carefully consider each of the recommendations, noting where action has already been taken or has always been best practice as well as crucially where we can go further."
Progress Timeline
Initial status based on Scottish Government and City of Edinburgh Council responses to the Edinburgh Tram Inquiry Report (September 2023).