Value judgments in the analysis and synthesis of evidence

Objective: To describe the principal role of value judgments in the analysis and synthesis of evidence as they are involved in systematic reviews, meta-analyses, and health technology assessments. Method: Using the tools of conceptual analysis, we characterize three main types of value judgments and propose an outline of how to enhance the appropriate role of value judgments in the process of analyzing and synthesizing evidence. Results: The production, analysis, and synthesis of evidence involve value judgments characterized as preferences of persons or groups that cannot be validated by appeal to facts alone. Because preferences across individuals can vary, value judgments can be a source of bias in science and unwarranted variation in the application of scientific evidence. However, it is not possible or desirable to eliminate all value judgments in the process from production to synthesis of evidence. Conclusion: With respect to the value judgments that shape the analysis and synthesis of evidence, review authors should disclose and justify choices related to the three key value judgments outlined in this paper. Authors should also highlight how their value judgments differ from the stated or implicit value judgments of previously published reviews on the same topic.