ArticleSystematic reviews2023
Definition, harms, and prevention of redundant systematic reviews.
Article in Systematic reviews, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
15 citing papers in PubMed, 3 syntheses or guidelines pooled it.
- The Certainty of the Evidence on Plant- vs Meat-Predominant Dietary Patterns and Depression: An Umbrella Review.Nutrition reviews · 2026Pooled it
- Effectiveness of exercise therapy for osteoarthritis: an overview of systematic reviews and randomised controlled trials.RMD open · 2026Pooled it
- Grading the strength and certainty of the scientific evidence of the bidirectional association between periodontitis and noncommunicable diseases: an umbrella review.Evidence-based dentistry · 2025Pooled it
- Why the current evidence does not support classifying e-cigarettes as likely carcinogenic to humans.Carcinogenesis · 2026Article
- Development and content validation of an interprofessional collaboration model for child sexual abuse prevention in primary health care.BMC primary care · 2026Article
- Determining the Conclusiveness of Systematic Review Evidence : A Scoping Review of Methodological Approaches.Annals of internal medicine · 2026Article
- Clinical research on homeopathic preparations: protocol template for a series of systematic reviews.Systematic reviews · 2026Article
- Exploring duplication in reviews of Long COVID: 2020-2023.Systematic reviews · 2026Article
- A Teaching Reform Practice to Improve Research Literacy of Veterinary Postgraduate Students Based on Evidence-Based Veterinary Medicine.Veterinary sciences · 2026Article
- Text recycling: defining the boundaries of acceptable reuse of one's own work.Conservation physiology · 2026Article
- Will AI become our Co-PI?NPJ digital medicine · 2025Review
- Natural product extracts for ischemic stroke: a methodological evaluation and meta-epidemiological analysis.Frontiers in pharmacology · 2025Article
- The impact of investigator bias in nutrition research.Frontiers in nutrition · 2025Article
- Evidence-based research.Systematic reviews · 2024Article
- Comparative analysis of Cochrane and non-Cochrane reviews over three decades.Systematic reviews · 2024Observational
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundAlong with other types of research, it has been stated that the extent of redundancy in systematic reviews has reached epidemic proportions. However, it was also emphasized that not all duplication is bad, that replication in research is essential, and that it can help discover unfortunate behaviors of scientists. Thus, the question is how to define a redundant systematic review, the harmful consequences of such reviews, and what we could do to prevent the unnecessary amount of this redundancy. MAIN BODY: There is no consensus definition of a redundant systematic review. Also, it needs to be defined what amount of overlap between systematic reviews is acceptable and not considered a redundancy. One needs to be aware that it is possible that the authors did not intend to create a redundant systematic review. A new review on an existing topic, which is not an update, is likely justified only when it can be shown that the previous review was inadequate, for example, due to suboptimal methodology. Redundant meta-analyses could have scientific, ethical, and economic questions for researchers and publishers, and thus, they should be avoided, if possible. Potential solutions for preventing redundant reviews include the following: (1) mandatory prospective registration of systematic reviews; (2) editors and peer reviewers rejecting duplicate/redundant and inadequate reviews; (3) modifying the reporting checklists for systematic reviews; (4) developing methods for evidence-based research (EBR) monitoring; (5) defining systematic reviews; (6) defining the conclusiveness of systematic reviews; (7) exploring interventions for the adoption of methodological advances; (8) killing off zombie reviews (i.e., abandoned registered reviews); (9) better prevention of duplicate reviews at the point of registration; (10) developing living systematic reviews; and (11) education of researchers.
conclusionsDisproportionate redundancy of the same or very similar systematic reviews can lead to scientific, ethical, economic, and societal harms. While it is not realistic to expect that the creation of redundant systematic reviews can be completely prevented, some preventive measures could be tested and implemented to try to reduce the problem. Further methodological research and development in this field will be welcome.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.