Trends in the Distribution of P Values in Epidemiology Journals: A Statistical, P-Curve, and Simulation Study
- Sarah F Ackley 1, Ryan M Andrews 2, Christopher Seaman 3, Michael Flanders 1, Ruijia Chen 2, Jingxuan Wang 3, Grissel Lopes 2, Kendra D Sims 2, Peter Buto 1, Erin Ferguson 3, Isabel Elaine Allen 3, M Maria Glymour 2
- 1Department of Epidemiology, Brown University, Providence, RI.
- 2Department of Epidemiology, Boston University, Boston, MA.
- 3Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA.
- 0Department of Epidemiology, Brown University, Providence, RI.
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View abstract on PubMed
Summary
This summary is machine-generated.Epidemiologists are shifting from P values to confidence intervals. Analysis shows P values have decreased, but this is likely due to increased statistical power, not reduced P hacking.
Area Of Science
- Epidemiology
- Biostatistics
Background
- Concerns exist regarding null-hypothesis statistical-significance testing, P hacking, and reproducibility in epidemiology.
- Epidemiologists have recommended reporting confidence intervals and reducing reliance on P values.
Purpose Of The Study
- To investigate whether efforts to de-emphasize P values have altered their distribution in epidemiological research.
- To analyze trends in P value distributions over time in major epidemiology journals.
Main Methods
- Scraped P values (N=25,288) from 21,332 abstracts published between 2000-2024 in four major epidemiology journals using ChatGPT's 4o model.
- Calculated P values from estimates and confidence intervals.
- Evaluated trends over time and fitted to expected P value distributions, simulating scenarios with and without changes in statistical power.
Main Results
- Average P values decreased from 2000 to 2024.
- The proportion of P values falling just below the 0.05 significance threshold also decreased.
- Model fits suggest an increase in statistical power over the study period.
Conclusions
- The observed trends in P value distribution are consistent with increased statistical power, rather than a reduction in P hacking.
- While the frequency of P values near the 0.05 threshold has modestly declined, this is attributed to enhanced statistical power.
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