The The Green Book: Appraisal and Evaluation in Central Government is the UK government’s authoritative guidance on evaluating public policies, programs, and investment projects. Published by the HM Treasury, it provides a standardized framework for economic, financial, social, and environmental appraisal to support evidence-based decision-making. The Green Book emphasizes cost-benefit analysis (CBA), highlighting the importance of quantifying and monetizing project costs and benefits, including non-market impacts such as environmental and social effects. It outlines methods for risk assessment, discounting future costs and benefits, sensitivity analysis, and distributional impacts. The guidance also covers project evaluation and post-implementation review to assess whether objectives were achieved and lessons learned. Overall, the Green Book ensures that public investments in the UK are efficient, transparent, and aligned with government policy objectives, providing a benchmark for high-quality project appraisal and evaluation.
