Optimism Bias in Business Cases
Edinburgh Tram Inquiry · Edinburgh Tram Inquiry Report · Issued 12 September 2023 · Addressed to: Scottish Government
Source — verbatim from the inquiry
●Inquiry recommendation
All Business Case versions must include risk assessments accounting for optimism bias per published government guidance.
Edinburgh Tram Inquiry, Edinburgh Tram Inquiry Report · 12 Sep 2023 Source PDF →
Published evidence summary
Publicly available evidence relating to this recommendation:
- Scottish Government Green Book supplementary guidance requires consideration of optimism bias in Business Cases, but no published update specifically responding to this recommendation has been identified to March 2026.
Sources
Response — verbatim from government
●Scottish Government
The Scottish Government stated it already operates in line with best practices for governance and light rail delivery. Source: Transport Secretary Statement, 2 November 2023.
Scottish Government · 2 Nov 2023 Written response →
Evidence trail — what's actually happened since
- 2 Nov 2023 Initial status based on Scottish Government and City of Edinburgh Council responses to the Edinburgh Tram Inquiry Report (September 2023). Source →
Each entry above links to a primary source — gov.uk written statement, consultation response document, or inspection report. The Index does not characterise government intent; it tracks what has been published.
How this page is built
Source and Response are verbatim from primary documents. The Evidence trail records published activity since — written statements, consultation outcomes, inspection findings, parliamentary references. The Index does not paraphrase or characterise intent; it tracks what has been published. Where the evidence is the absence of action (a missed deadline, a slipped timetable), that absence is documented from primary sources rather than inferred.
This recommendation's data is verified periodically against primary sources. The Index is monitored for staleness weekly.