Eta² tamanho efeito
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Eta² effect size calculator measures the proportion of total variance explained by a factor in an ANOVA study. The formula used is Eta² = SSB / SS_total, where SSB is the sum of squares between groups and SS_total is the total sum of squares. This index ranges from 0 to 1, with higher values indicating a stronger effect of the analyzed factor.
It is particularly useful in experimental or group-comparison studies, such as medical trials, educational research, or social sciences. For example, it can assess the impact of different teaching methods on student performance or compare the effectiveness of business strategies. Remember that Eta² does not imply causation, only the magnitude of the observed effect.
When using the calculator, ensure that SSB and SS_total data come from a valid ANOVA. Values close to 0 suggest minimal impact from the factor, while values above 0.14 (in social sciences) may be considered large. Interpret cautiously in small samples, as Eta² can overestimate effects in such cases.
Frequently asked questions
How do I interpret Eta² values?
Values near 0 indicate minimal effect, while values above 0.14 in social sciences are considered large. Guidelines may vary by field of study.
Is Eta² the same as partial Eta²?
No. Eta² measures total variance explained, while partial Eta² focuses on a single factor in multi-variable studies.
Can Eta² be used in non-experimental studies?
Yes, but cautiously. Eta² describes associations between variables without proving causality, especially in observational research.
What if the result is very close to 1?
An Eta² near 1 suggests the factor explains almost all variance. Check for overfitting or redundant variables in the model.