Abstract
Central government guidance seeks to ensure and enhance the quality of practice and decision-making across – and sometimes beyond – government. The Magenta Book, published by HM Treasury, is the key UK Government resource on policy evaluation, setting out central government guidance on how to evaluate policies, projects and programmes. The UK Centre for the Evaluation of Complexity Across the Nexus was invited to contribute its expertise to the UK Government’s 2020 update of the Magenta Book by developing an accompanying guide on policy evaluation and ‘complexity’. A small multidisciplinary team worked together to produce a set of guidance, going through multiple stages of work and drawing on a variety of sources including academic and practitioner literature and experts and stakeholders in the fields of evaluation, policy and complexity. It also drew on Centre for the Evaluation of Complexity Across the Nexus’ own work developing and testing evaluation methods for dealing with complexity in evaluation. The resulting Magenta Book 2020 Supplementary Guide: Handling Complexity in Policy Evaluation explores the implications of complexity for policy and evaluation and how evaluation can help to navigate complexity. This article, designed primarily for practitioners who might be interested in this guidance and how it was developed, describes the processes involved, particularly related to the interdisciplinary dialogue and consultation with other key stakeholders that this involved. It also briefly outlines the content and key messages in the guidance, with reflections on the experiences of the authors in developing the guide – including the challenges and insights that arose during the process, particularly around the challenges of communicating complexity to a broad audience of readers.