Replicability in the context of systematic reviews: A call for a framework with considerations regarding duplication, overlap, and intentionality
Letter to the editor
Reproducibility and replicability are considered central to the development and evolution of science, as they should ensure the efficient generation of reliable knowledge [[1. Much has been written about the “reproducibility crisis” [[2 and “replicability crisis” [ as a serious threat to all experimental sciences.
]Although there are manuscripts pondering the definitions of reproducibility and replicability in general [ we consider that there are particular considerations regarding these definitions in the context of systematic reviews that deserve further attention.
]Others reported that reproducibility involves reanalyzing the data collected in a study using the same computational steps and analytic code as the original study, and replicability is conducting a new study designed to address the same question(s) of a prior study [
]. However, just like suggested definitions of direct, and conceptual replication of systematic reviews [ this implies intentionally replicating a study.
. In that case, they are not doing a purposeful replication in any sense. Such “non-intentional replication” reviews will then be considered a replication simply because they have a very similar/same research question compared to the existing review(s). In all non-intentional replications of systematic reviews, this brings up the consideration of what we mean by the same/similar question. Even if the clinical question is really exactly the same, there can be differences arising from the PICO and in the next step from the eligibility criteria. Language restrictions, for example, could play a large role here . Reproducibility and replicability are expected to reduce research waste and increase the value of evidence [. Although excessive duplication of systematic reviews  is certainly contributing to research waste, there may be legitimate reasons for conducting new, overlapping systematic reviews. But, then, legitimate overlapping systematic reviews should not necessarily be considered replicated, unnecessary, and contributing to research waste.