HM Treasury logged an Oct. 28 update to UK guidance used in public appraisals to value future social effects, but its notice does not explain what was changed.
The Green Book, the UK government’s appraisal framework, calls for discounting so effects expected in future years can be assessed in present-value terms alongside current impacts. The supplementary guidance explains how to derive the social time preference rate.
A Feb. 5, 2026, revision gathered discounting material previously located in separate parts of the Green Book. HM Treasury said that version added more explanation of how to calculate the discount rate and tables showing factors for health and for lower long-term discount rates.
The GOV.UK page says the supplementary guidance was first published in 2013. Its Oct. 28 entry records the latest update but provides no further description of the changes.