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Updated: Jun 16, 2026
04:53
A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
Data integrity of the 223 randomized controlled clinical trials produced by multiple groups centered around a single
Daan Langeveld1, Buğra Sipahioğlu1, Marlena Oebel1
1Institute of Psychology, Department of Clinical Psychology, Leiden University, Leiden, The Netherlands.
Research Integrity and Peer Review
|June 13, 2026
Summary
This study found that randomized controlled trials (RCTs) by a specific research team lacked expected variability in baseline data and participant dropout. These findings question the scientific integrity and clinical value of their published RCTs.
Area of Science:
- Biostatistics
- Clinical Trials Methodology
- Research Integrity
Background:
- Investigated unusual consistency in baseline variables and dropout rates in randomized controlled trials (RCTs) from a specific research team.
- Defined this group of RCTs by the presence of a 'key author' within the research team.
- Assessed the trustworthiness, scientific, and clinical value of these RCTs.
Purpose of the Study:
- To determine if RCTs produced by a particular research team exhibit unusual consistency in baseline characteristics and participant dropout.
- To evaluate the scientific and clinical value of these RCTs based on data trustworthiness.
Main Methods:
- Conducted systematic searches across Embase, PubMed, and Web of Science for RCTs authored by the identified team.
- Performed preregistered analyses to test for sampling variability in baseline characteristics and participant flow (even vs. odd dropout, equal dropout).
- Utilized control RCTs on similar topics from other research groups for comparison.
Main Results:
- Found strong evidence against expected sampling variability in 223 RCTs by the team (Bayes Factor > 100,000).
- Observed significantly non-random proportions of even vs. odd dropout (0.76) and more frequent equal dropout compared to control RCTs.
- These anomalies were not explained by randomization methods or sample size, and were strongest when the 'key author' held primary authorship.
Conclusions:
- The observed data suggest that the RCTs from this team were unlikely generated through proper randomization processes.
- Participant flow in these trials appears implausible, raising concerns about data integrity.
- The scientific and clinical value of RCTs produced by this research team is questionable.
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