This problem is addressed in ROBIS and MECIR. Data extraction for outcomes in individual studies should be performed carefully and independently verified in order to ensure accuracy. Double counting can occur when multiple included papers report data from the same trials.
Articles that support this problem:
A case study of binary outcome data extraction across three systematic reviews of hip arthroplasty: errors and differences of selection
2013 : Bmc research notes
High prevalence but low impact of data extraction and reporting errors were found in Cochrane systematic reviews
2005 : Journal of clinical epidemiology
Data extraction methods: an analysis of internal reporting discrepancies in single manuscripts and practical advice
2020 : Journal of clinical epidemiology
Errors in systematic reviews: an example of computed tomography screening for lung cancer
2014 : European journal of cancer prevention
Errors in the conduct of systematic reviews of pharmacological interventions for irritable bowel syndrome
2010 : American journal of gastroenterology
Different patterns of duplicate publication: an analysis of articles used in systematic reviews
2004 : Jama
Incorrect inclusion of individual studies and methodological flaws in systematic review and meta-analysis
2014 : British journal of general practice
Missing binary data extraction challenges from Cochrane reviews in mental health and Campbell reviews with implications for empirical research
2017 : Research synthesis methods
Cochrane has not consistently followed the COPE guidelines
2020 : European journal of clinical investigation
Increased risks for random errors are common in outcomes graded as high certainty of evidence
2019 : Journal of clinical epidemiology
Selecting studies (not reports) as the unit of interest of systematic reviews and meta-analyses: an essential practice
2020 : International journal of obesity
Disagreements in meta-analyses using outcomes measured on continuous or rating scales: observer agreement study
2009 : Bmj
Letter to the Editor concerning "The role of non-rigid cervical collar in pain relief and functional restoration after whiplash injury: a systematic review and a pooled analysis of randomized controlled trials" by Ricciardi L, et al. (Eur Spine J; [2019] 28:1821-1828)
2020 : European spine journal
Appraising the exercise oncology literature: a reminder of the rigour needed in systematic reviews
2019 : British journal of sports medicine
Validity of data extraction in evidence synthesis practice of adverse events: reproducibility study
2022 : Bmj
RE: Physical Activity and the Risk of Liver Cancer: A Systematic Review and Meta-Analysis of Prospective Studies and a Bias Analysis
2020 : Journal of the national cancer institute
Importance of excluded duplicates reporting in a systematic review
2021 : World journal of pediatrics
Errors and Biases in Meta-analysis of the Prevalence of Olfactory Dysfunction in Patients With COVID-19
2021 : Otolaryngology - head and neck surgery (united states)
Methodological considerations for systematic review and meta-analysis of Xpert bladder cancer monitor
2022 : Urologic oncology: seminars and original investigations
Letter to the editor regarding "The effectiveness of manual therapy on pain, physical function, and nerve conduction studies in carpal tunnel syndrome patients: a systematic review and meta-analysis"
2022 : International orthopaedics