How To Calculate Mean Effect Size In A Meta-Analysis

Mean effect size in meta-analysis is a statistical measure that combines the results of multiple studies to provide an overall estimate of the size of an effect. It’s crucial for understanding the practical significance of research findings.

How to Use This Calculator

1. Enter the number of studies (n).
2. Enter the effect sizes for each study, separated by commas.
3. Enter the weights for each study, separated by commas. Weights are typically the sample size of each study.
4. Click ‘Calculate’.

Formula & Methodology

The formula for calculating the mean effect size in a meta-analysis is:

Mean Effect Size = (∑(Effect Size * Weight)) / ∑Weight

The calculator uses this formula to compute the mean effect size.

Real-World Examples

Data & Statistics

Example Data for Mean Effect Size Calculation

Study	Effect Size	Weight (Sample Size)
1	0.5	100
2	0.3	150

Expert Tips

• Always ensure the data is normally distributed before calculating the mean effect size.
• Consider using a random-effects model if there is heterogeneity between studies.

Interactive FAQ

What if my data is not normally distributed?

You may need to use a non-parametric alternative, such as the median effect size.

For more information, see the CDC’s guide to statistics and the Mendeley guide to meta-analysis.