This guide is the 2026 update to the Magenta Book, the United Kingdom Government’s central guidance on evaluation. As the most significant revision in government evaluation standards since 2020, it marks a major milestone for evidence-based policymaking.

It provides guidance on evaluation in government: its scoping, design, conduct, use and dissemination as well as the capabilities required of government evaluators. It provides guidance on how to incorporate evaluation through the design, implementation, delivery and review stages of policymaking. It also explains how results can be interpreted and presented, and what should be considered in this process.

The Book is written for the policy, delivery and analytical professions, all of which are responsible for securing and using good evidence. 

This update ensures that the guidance reflects the advances in evaluation practice since the previous 2020 version. In addition to minor changes to the main book, six areas received substantive
updates:

1. value for money
2. test and learn
3. the relationship between benefits management and evaluation
4. transparency
5. artificial intelligence
6. place-based evaluation.

The guide is provided with a summary of updates and Annex A provides detailed guidance on the range of evaluation methods. There are several supplementary guides to specific types of evaluations that are appropriate for specific contexts available on the website page.