Eta-squared
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Eta-squared (η2) is a measure of effect size for use in ANOVA.
Analagous to R2 from multiple linear regression.
η2
- = SSbetween / SStotal = SSB / SST
- = proportion of variance in Y explained by X
- = Non-linear correlation coefficient
- = proportion of variance in Y explained by X
Ranges between 0 and 1.
Interpret as for r2 or R2; a rule of thumb:
- .01 ~ small
- .06 ~ medium
- .14 ~ large
The eta-squared column in SPSS F-table output is actually partial eta-squared (
) in versions of SPSS prior to V 11.0. [1]
η2 is not provided by SPSS – needs to be calculated separately = Between-Groups Sum of Squares / Total Sum of Squares.
R2 is provided at the bottom of SPSS F-tables is the linear effect as per MLR – however, if an IV has 3 or more non-interval levels, this won’t equate with η2.
[edit] References
- ↑ CAUTIONARY NOTE ON REPORTING ETA-SQUARED VALUES FROM MULTIFACTOR ANOVA DESIGNS. Pierce C.A., Block, C.A. & Aguinis, H. Educational and Psychological Measurement 64(6), 2004.
