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Published on: September 7, 2018
Specific instructions for estimating unclearly reported blinding status in randomized trials were reliable and valid
Elie A Akl1, Xin Sun, Jason W Busse
1Department of Medicine, State University of New York at Buffalo, Buffalo, NY 14215, USA. elieakl@buffalo.edu
Journal of Clinical Epidemiology
|December 28, 2011
Summary
This study found that using "probably yes" and "probably no" improved the assessment of blinding in randomized trials. This method enhances reliability for most participants, except possibly data analysts.
Area of Science:
- Clinical Trials Methodology
- Research Integrity
- Evidence-Based Medicine
Background:
- Assessing blinding in randomized trials is crucial for minimizing bias.
- Unclear reporting of blinding status often complicates trial evaluations.
- Standardized instructions are needed to reliably classify blinding procedures.
Purpose of the Study:
- To evaluate the reliability and validity of specific instructions for classifying blinding in randomized trials.
- To determine if using "probably done" or "probably not done" improves blinding assessment compared to "unclear."
Main Methods:
- Two independent reviewers assessed blinding for patients, providers, data collectors, adjudicators, and analysts in 233 randomized trials.
- Detailed instructions and a four-option response scale were used.
- Author verification was obtained for 46% of trials to assess validity.
Main Results:
- The percentage of unclear blinding status ranged from 48.5% (patients) to 84.1% (data analysts).
- Reliability (kappa values) ranged from moderate (0.42 for data analysts) to substantial (0.71 for patients).
- Consensus between reviewers and author-verified data showed high agreement (84.1%–100%).
Conclusions:
- The proposed "probably yes" and "probably no" categories enhance the assessment of blinding in randomized trials.
- This approach appears reliable and valid for most trial components, with potential limitations for data analysts' blinding.
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