This article discusses the integration of a diagnostic lens in qualitative or mixed methods evaluations, arguing that this will improve quality: in particular, it will improve transparency, credibility and reliability of evaluation findings.We start by unpacking the notion of evaluation quality and pointing out the typical weaknesses of qualitative methods. We then introduce the basic notions of diagnostic approaches and how they relate to theory-based evaluation, process tracing, and Bayesian updating, arguing for the merits of taking a formal Bayesian approach, founded on the confusion matrix, which amongst else reduces confirmation bias and conservatism. This article draws parallels between the process tracing tests and elements of the confusion matrix.

中文翻译：

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质量质量：定性评估的诊断方法

本文讨论了在定性或混合方法评估中整合诊断镜头，认为这将提高质量：特别是，它将提高评估结果的透明度、可信度和可靠性。我们首先解开评估质量的概念并指出定性方法的典型弱点。然后，我们介绍了诊断方法的基本概念以及它们与基于理论的评估、过程跟踪和贝叶斯更新的关系，论证了采用基于混淆矩阵的正式贝叶斯方法的优点，其中包括减少确认偏差和保守主义。本文将过程跟踪测试与混淆矩阵的元素进行了比较。