Mauchly's sphericity test

Mauchly's sphericity test is used to test the assumption of sphericity in within-subject ANOVAs. This assumption is that: the difference scores between each within-subject variable have similar variances.

If Mauchly's sphericity test is significant (p < .05), then sphericity should not be assumed and adjustments to the degrees of freedom should be made using an adjustment such as:

1. Greenhouse-Geisser
2. Huyn-Feldt
3. Lower-bound

Greenhouse-Geisser is commonly used and recommended.

See also

• Mauchly's sphericity test (Wikipedia)

External links

• An introduction to sphericity
• ANOVA with SPSS