by **reason180** » Thu Jun 10, 2021 3:40 am

Greetings.

I think jamovi's "no correction" is in fact Fisher's LSD. The p values for Fisher's LSD are in fact not corrected for familywise error ( https://www.graphpad.com/support/faqid/176/ (the "protection" is that you don't look at post-hoc results unless the relevant ANOVA main-effects and/or interactions are significant)). Therefore, I had assumed that "no correction" meant Fisher's LSD.

For the emmeans R package, I've not been able to find documentation about the meaning of "no correction." However, just now, using the Tooth Growth data set, I ran an ANOVA assessing tooth length as a function of dose (there was just one factor in the ANOVA). For the post hoc tests, I chose "no correction." I then ran the same ANOVA in SPSS but selected "LSD" (there's no "no correction" option in SPSS). The post hoc test results were identical for jamovi and SPSS. Consequently, I suspect that jamovi's "no correction" and LSD are exactly the same thing.

Perhaps the name of the option in jamovi should be changed from "No Correction" to "No Correction (LSD)"?

Regards,

--

Rich Anderson

Bowling Green State University