Determining the Conclusiveness of Systematic Review Evidence : A Scoping Review of Methodological Approaches.

Abstract

Systematic reviews can inform research, funding, and guideline decisions. However, it can be challenging to know whether a systematic review has answered a research question conclusively, and it is unclear which methods exist for such assessments. To map methods related to determining the conclusiveness of systematic reviews. Medline (Ovid), Embase (Ovid), and Web of Science until 26 September 2025. Any documents describing methods for determining the conclusiveness of systematic reviews. Two reviewers independently extracted data from the primary references of the included methods. Forward citation searches of the primary references were then conducted to identify examples of application of the methods. Sixty-two methods related to assessing the conclusiveness of systematic review results were identified; 45 of these had at least 1 example of their application. The 62 methods were categorized into 3 approaches comprising 23 groups. Mathematical approaches for meta-analyses included 29 methods categorized into 9 groups, such as the fail-safe number, Barrowman's <i>n</i>, and the fragility index. Mathematical approaches for cumulative meta-analyses comprised 15 methods categorized into 7 groups, including trial sequential analyses, sequential meta-analyses, and the law of the iterated logarithm methods. Nonmathematical approaches included 18 methods across 7 groups, such as GRADE (Grading of Recommendations Assessment, Development and Evaluation) frameworks, Ottawa methods, and the RAND method. There was no assessment of which methods perform better. Not all methods strictly aimed to determine conclusiveness. This review identified various methods related to assessing the conclusiveness of systematic reviews to enhance their ability to guide research, funding, and clinical decisions. Western Norway University of Applied Sciences. (Protocol registered in the Open Science Framework [https://osf.io/dthps]).