Background
Prospective meta-analysis (PMA) is an approach to synthesising evidence that has the potential to address the limitations and sources of bias associated with traditional retrospective systematic reviews and meta-analyses.1,2 In a PMA, research efforts are coordinated to maximise the use of data to find answers to important research questions.1,3 However, the terminology and definitions used to date have resulted in some confusion and inconsistency. This threatens successful implementation and interpretation of PMA.
Objective
The aim of this project was to clarify PMA terminology, definition, and classification.
Methods
PubMed, Embase, Cochrane Database of Systematic Reviews and PROSPERO were systematically searched, and experts were contacted, to identify all planned, published, or ongoing PMA. The search results were then grouped and the different terminologies, definitions, and study types described. Cochrane PMA Methods group members engaged in a structured expert workshop to refine the definition of PMA and develop classifications, based on the findings of the search.
Results
We identified 1,056 entries for title and abstract screening, 274 of those were included for full-text screening. There was great variation in the terminology, reporting, and definitions of the identified PMA. The structured expert discussion resulted in a revised definition of PMA and its subcategories, and will inform the future development of guidelines on how to conduct and report PMA.
Discussion
PMA are adaptive, efficient, and collaborative. This work will improve understanding of PMA in the research community and enable more researchers to conduct successful PMA, thereby maximising data use and reducing research waste.