Effect sizes in memory research.

Area of Science:

• Psychology
• Cognitive Science
• Research Methodology

Background:

• Effect sizes are frequently omitted or under-discussed in research articles.
• Accurate interpretation of effect sizes is crucial for evaluating research findings.
• Commonly reported effect size measures include partial eta squared and Cohen's d.

Purpose of the Study:

• To provide researchers with updated guideline values for interpreting effect sizes in memory research.
• To compare observed effect sizes in memory research with established generic guidelines.
• To offer practical tools for reporting and contextualizing effect sizes in scientific publications.

Main Methods:

• Collected effect size data (partial eta squared and d) from memory research papers published in 2010.
• Analyzed the distributions of observed effect sizes.
• Compared these distributions with Cohen's standard small, medium, and large guideline values.

Main Results:

• Cohen's guideline values for Cohen's d aligned well with observed distributions in memory research.
• Cohen's guideline values for partial eta squared were considerably lower than those observed in current memory research.
• Cumulative frequency tables for partial eta squared and d were generated.

Conclusions:

• Interpreting effect sizes should consider domain-specific guidelines or empirical distributions from published research.
• Existing generic guidelines for partial eta squared may not accurately reflect current memory research.
• The provided cumulative frequency tables can aid researchers in reporting and contextualizing their effect sizes.