Related Experiment Video
Updated: Jun 16, 2026

The Adjuvant Efficacy of Angong Niuhuang Pill in the Treatment of Viral Encephalitis: A Meta-Analysis of Randomized Controlled Trials
Published on: April 19, 2024
A novel application of the file drawer formula: rejected study bias in meta-analysis
1Department of Health, Physical Education and Recreation, Chicago State University, 9501 S. King Drive, Chicago, IL 60628, USA. ereed@csu.edu
Abstract:
The file drawer formula in meta-analysis estimates the number of null difference effect sizes (ESs) from unpublished studies in researcher file drawers that are necessary to reduce the mean ES to a magnitude no longer considered practical or meaningful. Unlike the file drawer concept, this paper proposes a novel use of Orwin's 1983 formula that produces an estimate of the potential bias in the mean ES due to missing ESs from studies that were located and retrieved, but rejected because of insufficient data for ES calculation.
Related Concept Videos
Friedman Two-way Analysis of Variance by Ranks
Bonferroni Test
The means of different samples are first paired in all possible combinations.
The null hypothesis of the...
Bias in Epidemiological Studies
Bias
In statistics, a sampling bias is created when a sample is collected from a population, and some members of the population are not as likely to be chosen as others (remember, each member...
Study Design in Statistics
Does aspirin reduce the risk of heart attacks? Is one brand of fertilizer more effective at growing roses than another? Is fatigue as dangerous to a driver as the influence of alcohol? Questions like these are answered using randomized experiments with proper...
Confirmation Biases
