We use some essential cookies to make this website work.
We’d like to set additional cookies to understand how you use GOV.UK, remember your settings and improve government services.
We also use cookies set by other sites to help us deliver content from their services.
You have accepted additional cookies. You can change your cookie settings at any time.
You have rejected additional cookies. You can change your cookie settings at any time.
Departments, agencies and public bodies
News stories, speeches, letters and notices
Detailed guidance, regulations and rules
Reports, analysis and official statistics
Consultations and strategy
Data, Freedom of Information releases and corporate reports
Supplementary guidance to the Green Book on estimates for a project's costs, benefits and duration in the absence of robust primary evidence.
Description of the statistical methods and techniques used to create and analyse monthly estimates for personal well-being related to optimism and concerns for the UK. This is the first time that we are publishing these new questions as Experimental Statistics.
Investigates the phenomenon of optimism bias in UK rail infrastructure projects.
Peer review of Oxford Global Projects research report on the rate of optimism bias uplifts used in transport appraisal.
The third paper in a series of Homes England research reports on measuring social value.
A workbook of reference class forecast curves that can be used in uncertainty analysis.
A report on the updated evidence for optimism bias uplifts for transport appraisals.
Don’t include personal or financial information like your National Insurance number or credit card details.
To help us improve GOV.UK, we’d like to know more about your visit today. Please fill in this survey (opens in a new tab).