Is there an issue with the output of the Huynh-Feldt correction when running an ANOVA for both between and within factors (mixed design) in R? My issue is that when I run a 'within-subject (only)' ANOVA using either the 'Anova' or 'ezANOVA' functions, the output for the Huynh-Feldt correction is the exact same I get when using SPSS. However when I run an ANOVA on a mixed design, and consider both between and within subject effects using either the 'Anova' or 'ezANOVA' functions, my Greenhouse-Geisser corrections match up to SPSS, but the Huynh-Feldt corrections are slightly off compared to the output from SPSS? Any reason why this could be? I appreciate any advice/help anyone could provide!
If there were an error in Anova it would also be in ezANOVA because Mike Lawrence built ez on John Fox's Anova package. And the Anova package in turn uses the standard R
(My speculation about why they haven't fixed it is similar to the reason Excel remains buggy... they have a greater obligation to major customers to be bug compatible than to be correct. Fixing this would be admitting they were wrong as well. Although, if it were done in 1992 it would have been reasonable. Now it's just a great argument for open source. Alternatively, they just might not care. I wonder if one simply tests it's output against the other?)