I² Heterogeneity Calculator
Cochran's Q, I², H², τ² and pooled estimates for a meta-analysis.
Enter your values to see the result.
τ² uses the DerSimonian–Laird estimator and the I² interval uses the test-based method of Higgins & Thompson (2002). The Cochrane Handbook bands (0–40% might not be important, 30–60% moderate, 50–90% substantial, 75–100% considerable) overlap on purpose: judge I² together with the direction and size of effects.
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- Leave-One-Out Meta-analysis — Find which study drives the heterogeneity.
- Meta-analysis Effect Converter — Get log effects and SEs from published results.
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How to use the I² Heterogeneity Calculator
Cochran's Q, I², H², τ² and pooled estimates for a meta-analysis.
- 1 Paste one study per line as effect, standard error (or enter Q and the number of studies).
- 2 Choose the confidence level.
- 3 Read I², its interval and the pooled estimates.
Example and practical tips
Six studies with Q = 6.39 on 5 degrees of freedom give I² = 21.7%, which might not be important heterogeneity.
Further reading
Frequently asked questions
How do I interpret I²?
The Cochrane Handbook gives overlapping bands: 0–40% might not be important, 30–60% moderate, 50–90% substantial and 75–100% considerable.
Why show the I² confidence interval?
With few studies I² is very imprecise. A wide interval warns against reading too much into one value.
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