Re: [R-sig-eco] 2-way adonis (PERMANOVA) incl interaction - how to test for main effects?

2018-11-01 Thread Jari Oksanen
Gian, The marginal tests for one-term models had a problem in vegan 2.5-1 and vegan 2.5-2. This is fixed in vegan 2.5-3, so please upgrade. (It never occurred to me that people would use marginal tests for one-term models where the fitted model is compared against the empty model, and that

Re: [R-sig-eco] 2-way adonis (PERMANOVA) incl interaction - how to test for main effects?

2018-11-01 Thread Gian Maria Niccolò Benucci
Thank you very much Steve, I really appreciate you answer. I do not want to drop the main effects out form the model, I was just trying to understand how adonis works. I was more confused on how to use the adonis function correctly rather than on the theory that is behind it. I have an almost

Re: [R-sig-eco] 2-way adonis (PERMANOVA) incl interaction - how to test for main effects?

2018-11-01 Thread Steve Brewer
Gian, I am bit confused by what your concern is. First, if the imbalance is not that severe, the approach you take to analyzing a two-way permanova (type I, type II, type III ss) is not going to matter that much. Indeed, if the design were balanced, they would give you identical results.