Getting to Know Pain Effect Sizes-Guidelines for Effect Size and Sample Size in Global Pain Research

Area of Science:

• Pain research
• Psychology
• Biostatistics

Background:

• Interpreting effect sizes in pain research is crucial for understanding individual and group differences.
• Variability in effect sizes across geographical regions necessitates region-specific considerations.
• Standardized thresholds aid in consistent and meaningful interpretation of research findings.

Purpose of the Study:

• To establish reference thresholds for individual and group differences in pain research.
• To investigate geographical variations in these effect size thresholds.
• To provide sample size estimates for achieving desired statistical power.

Main Methods:

• Analysis of 5,294 effect sizes from 130 meta-analyses published in top pain journals.
• Data extracted from studies involving over 1 million participants.
• Calculation of effect size thresholds based on percentiles and regional analysis.

Main Results:

• Established thresholds: small (0.10), medium (0.30), large (0.40 for correlations; 0.70 for group differences).
• Significant regional variations observed, with Asia showing strongest large effects and North America the weakest.
• Exploratory thresholds provided for different continents.

Conclusions:

• Recommended reference values for small, medium, and large effects in pain research (Pearson's r: 0.10, 0.30, 0.40; Cohen's d/Hedges' g: 0.10, 0.30, 0.70).
• Emphasized the importance of considering regional variability and planning sample sizes accordingly.
• Proposed continent-specific exploratory thresholds to enhance interpretability.