Identifying and addressing conflicting results across multiple discordant systematic reviews on the same topic: A protocol for a replication study of the Jadad algorithm

Abstract

Introduction: An increasing growth of systematic reviews (SRs) presents notable challenges for decision-makers seeking to answer clinical questions. Overviews of systematic reviews aim to address these challenges by summarising results of SRs and making sense of potentially discrepant SR results and conclusions. In 1997, an algorithm was created by Jadad to assess discordance in results across SRs on the same topic. Since this tool pre-dates the advent of overviews, it has been inconsistently applied in this context. Our study aims to (a) replicate assessments done in a sample of overviews using the Jadad algorithm to determine if the same SR would have been chosen, (b) evaluate the Jadad algorithm in terms of utility, efficiency, and comprehensiveness, and (c) describe how overviews address discordance in results across multiple SRs. Methods and Analysis: We will use a database of 1218 overviews (2000-2020) created from a bibliometric study as the basis of our search for overviews assessing discordance. This bibliometric study searched MEDLINE (Ovid), Epistemonikos, and Cochrane Database for overviews. We will include any overviews using Jadad (1997) or another method to assess discordance. The first 30 overviews screened at the full-text stage by two independent reviewers will be included. We will replicate Jadad assessments in overviews. We will compare our outcomes qualitatively and evaluate the differences between our Jadad assessment of discordance and the overviews’ assessment. Ethics and Dissemination: No ethics approval was required as no human subjects were involved. In addition to publishing in an open-access journal, we will disseminate evidence summaries through formal and informal conferences, academic websites, and across social media platforms. This is the first study to comprehensively evaluate and replicate Jadad algorithm assessments of discordance in SRs.

How can clinicians choose between conflicting and discordant systematic reviews? A replication study of the Jadad algorithm

“…Cochrane SR guidance was followed when performing our study selection and data extraction [19]. Our protocol is registered as a preprint on the Research Square server [20].…”

“…First, we used consensus building strategies to develop clear instructions on how to operationalise the Jadad algorithm, and to ensure a consistent approach to assumptions and stepwise interpretation. We also adopted a systematic and transparent approach to address the objectives outlined in our protocol using SR guidance [20]. A comprehensive search strategy, including a search of the grey literature, was employed with no restrictions on language and publication status to minimise publication bias.…”

“…The data is freely available on the Open Science Framework at https://osf.io/ bpj2f. The final Jadad algorithm steps, our decision rules and supplementary results are found in the appendices, eight instructional videos are located at https://osf.io/2z7a5/, and our protocol is printed as a preprint on the Research Square server [20].…”