The value of complexity science and related approaches in policy evaluation have been widely discussed over the last 20 years, not least in this journal. We are now at a crossroads; this Special Issue argues that the use of complexity science in evaluation could deepen and broaden rendering evaluations more practical and rigorous. The risk is that the drive to better evaluate policies from a complexity perspective could falter. This special issue is the culmination of 4 years’ work at this crossroads in the UK Centre for the Evaluation of Complexity Across the Nexus. It includes two papers which consider the cultural and organisational operating context for the use of complexity in evaluation and four methodological papers on developments and applications. Together, with a strong input from practitioners, these papers aim to make complexity actionable and expand the use of complexity ideas in evaluation and policy practice.

中文翻译：

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复杂世界的政策评估：英国跨 Nexus 复杂性评估中心的实用方法和思考

在过去的 20 年中，复杂性科学和相关方法在政策评估中的价值已被广泛讨论，尤其是在本期刊中。我们现在正处于十字路口；本期特刊认为，在评估中使用复杂性科学可以深化和拓宽使评估更加实用和严格。风险在于，从复杂性的角度更好地评估政策的动力可能会动摇。本期特刊是英国跨 Nexus 复杂性评估中心在这个十字路口 4 年工作的结晶。它包括两篇论文，这些论文考虑了在评估中使用复杂性的文化和组织运营背景，以及四篇关于发展和应用的方法论论文。在从业者的大力投入下，