CECAN PRESS RELEASE (1 April 2020): CECAN guidance on complexity and policy evaluation published by HM Treasury

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HM Treasury has today (Wednesday 1 April 2020) updated the Magenta Book, UK Government’s central guidance on how to evaluate policies, projects and programmes. The Centre for the Evaluation of Complexity Across the Nexus (CECAN), based at the University of Surrey, was invited to contribute a supplementary guide on evaluation and complexity.


The Magenta Book 2020 Supplementary Guide: Handling Complexity in Policy Evaluation is based on three years’ research and development of evaluation methods by CECAN. It explains what complexity is, its implications, and how evaluators and policy makers can plan, deliver and use complexity-appropriate evaluation to help navigate complexity.


Professor Nigel Gilbert CBE, Director of CECAN at the University of Surrey, said: 

“The new edition of the Magenta Book, with its supplements, is important because it provides the government with up to date guidance on how to evaluate  public policies to check that they are effective and meet their objectives. Evaluation is challenging because of the complexity of the policy landscape. 

It is a significant step for HM Treasury to champion this guidance and for it to be adopted across government.  In doing so, the UK is taking a world leading position on policy evaluation. The work on which the Supplementary Guide is based was supported by the UKRI Economic and Social Research Council, the Natural Environment Research Council and government departments and agencies. ”


  • The Magenta Book 2020 Supplementary Guide is available to download here

  • Download the promotional flyer here.

  • Learn more about the Supplementary Guide with videos and presentation slides from CECAN’s launch event on 3 March 2020 here


More about CECAN

Launched in 2016, The Centre for the Evaluation of Complexity Across the Nexus (CECAN) receives funding from The Economic and Social Research Council (ESRC) and is hosted by the University of Surrey. CECAN has been transforming the practice of policy evaluation across the food, energy, water and environmental domains, to make it fit for a complex world. The Centre has achieved this through pioneering, testing and promoting innovative policy evaluation approaches with UK Government departments and other organisations.