Value of Flow Diagrams in Reports of Randomized Controlled Trials
Abstract
CONTEXT: Diagrams of the flow of participants through a clinical trial are recommended in the Consolidated Standards for Reporting of Trials (CONSORT) statement, but it is unclear whether such flow diagrams improve the quality of trial reports. OBJECTIVE: To examine the information contributed by flow diagrams and the completeness of reporting overall in reports of randomized controlled trials (RCTs) published in 5 general and internal medicine journals. DESIGN AND SETTING: Analysis of 270 reports of RCTs published in 1998 in the Annals of Internal Medicine (AIM; n = 19), BMJ (n = 42), JAMA (n = 45), The Lancet (n = 81), and The New England Journal of Medicine (NEJM; n = 83). MAIN OUTCOME MEASURES: Proportion of reports that included a flow diagram, information provided in flow diagrams, and completeness of reporting about flow of participants overall in flow diagrams or text. RESULTS: A total of 139 reports (51.5%) of RCTs included a flow diagram, but this varied widely among journals (AIM, 21.0%; BMJ, 38.1%; JAMA, 80.0%; The Lancet, 93.8%; and NEJM, 8.4%). Diagrams generally provided useful information, but only 73 (52.5%) included the number of participants who received allocated interventions and only 32 (23.0%) included the number of participants included in the analysis. In logistic regression analysis, overall completeness of reporting about flow of study participants was associated with publication of a flow diagram. CONCLUSIONS: Flow diagrams are associated with improved quality of reporting of randomized controlled trials. However, the structure of current flow diagrams is less than ideal. We propose a revised flow diagram that includes all important counts through the stages of parallel group trials.
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The absence of a flowchart hampers the analysis of the internal and external validity of the RCT, negatively impacting the clinical research report.
“The absence of a flowchart hampers the analysis of the internal and external validity of the RCT, negatively impacting the clinical research report (Egger 2001).”
From Adherence to the CONSORT statement of randomized clinical trials on dentin hypersensitivity treatment using mouthwashes (2025) · cites this paper as Egger 2001
Recommendations on the reporting of research can improve reporting quality.
“Recommendations on the reporting of research can improve reporting quality.”
From The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for Reporting Observational Studies (2007) · cites this paper as [15]
The CONSORT initiative has helped to improve the quality of reports of randomised trials.
“which has helped to improve the quality of reports of randomised trials [14,15].”
From The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for Reporting Observational Studies (2007) · cites this paper as [15]
Recommendations on the reporting of research can improve reporting quality.
“Recommendations on the reporting of research can improve reporting quality.”
From The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies (2014) · cites this paper as [15]
CONSORT has helped to improve the quality of reports of randomised trials.
“which has helped to improve the quality of reports of randomised trials [14,15].”
From The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies (2014) · cites this paper as [15]
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“The absence of a flowchart hampers the analysis of the internal and external validity of the RCT, negatively impacting the clinical research report (Egger 2001).”
Untitled work
von Elm, E., Altman, D. G., Egger, M., Pocock, S. J., Gøtzsche, P. C., & Vandenbroucke, J. P. (2007) · PLoS Medicine
- Authors
- Egger, M.
- Affiliations
- Medical Research Council (GB)
- Corresponding author
- Egger, Matthias
- ORCID
- Egger, Matthias
- Venue
- JAMA
- Publisher
- American Medical Association (AMA)
- Published
- 2001-04-18
- Volume
- 285
- Issue
- 15
- Pages
- 1996
- ISSN
- 0002-9955 (ISSN-L)
- 0098-7484
- OpenAlex
- W2084639013
- Cited by
- 317
- References
- 13
- Citations by year
- 2026: 1 · 2025: 5 · 2024: 5 · 2023: 14 · 2022: 3 · 2021: 8 · 2020: 9 · 2019: 5 · 2018: 9 · 2017: 6 · 2016: 8 · 2015: 8 · 2014: 10 · 2013: 9 · 2012: 11
- FWCI
- 30.27
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- JAMA (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
- Social Sciences › Decision Sciences › Information Systems and Management › Academic Publishing and Open Access
- Keywords
- flowcharts, CONSORT statement, reporting quality, randomized controlled trials
- MeSH terms
- Algorithms, Publishing, Quality Control, Randomized Controlled Trials as Topic
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