Estimating the false discovery risk of (randomized) clinical trials in medical journals based on published p-values

Ulrich Schimmack1, František Bartoš2,3

  • 1Department of Psychology, University of Toronto Mississauga, Mississauga, Canada.

Plos One
|August 30, 2023
PubMed

Insights

Most published scientific results are not false, but a 13% false positive risk exists with standard criteria. Lowering the significance threshold reduces this risk, though publication bias remains a concern.

Area of Science:

  • Medical Research Integrity
  • Biostatistics
  • Publication Bias

Background:

  • Concerns about the trustworthiness of scientific literature have been amplified by claims that most published results are false.
  • Previous empirical investigations into the rate of false-positive results have not definitively resolved this issue.

Purpose of the Study:

  • To propose and apply a novel method for estimating the false positive risk in published research.
  • To empirically evaluate the false positive risk in randomized clinical trials published in leading medical journals.

Main Methods:

  • Development of a new statistical approach to quantify false positive risk.
  • Application of the method to a dataset of clinical trial results from top-tier medical journals.
  • Analysis of the impact of traditional significance thresholds (e.g., alpha = 0.05) on false positive rates.

Main Results:

  • Contrary to widespread claims, the study found that the traditional significance level of alpha = 0.05 yields a false positive risk of 13%.
  • Adjusting the significance threshold to alpha = 0.01 substantially reduces the false positive risk to below 5%.
  • The study identified clear evidence of publication bias, which contributes to inflated estimates of effect sizes.

Conclusions:

  • The findings challenge the notion that most published research results are false.
  • A revised significance threshold (alpha = 0.01) offers a more reliable standard for reducing false positives in medical research.
  • Addressing publication bias is crucial for accurate effect size estimation and enhancing the overall trustworthiness of medical research findings.

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