Interesting that you ask; I was currently thinking about the same thing. Once a reviewer required us to do a Doubly Repeated Measures ANOVA "Doubly because the multiple variables and the repeated measures parts are both multivariate dimensions." At the time, I did not find how to do it in R, and was wondering just this week if something similar could be done using a mixed model...
Abraços, Rafael Maia --- "A little learning is a dangerous thing; drink deep, or taste not the Pierian spring." (A. Pope) Graduate Student - Integrated Bioscience University of Akron http://gozips.uakron.edu/~shawkey/ On Jul 23, 2010, at 7:08 PM, Peter Solymos wrote: > Kay, > > using strata (restricting permutations within time points, and not > within locations) in adonis makes some sense, given that permutation > tests assume independence. But that does not solve the problem of > dependence, but it is a good starter. If you have a before-after > control-treatment design, you might want to use the absolute > difference between observations and do the adonis on the matrix of > differences (the dissimilarity then will represent distance in terms > of absolute deviation between time points). However, this won't show > the sign of the change, which might be of interest. If you have larger > number of repeated observations, the MARSS package is just appeared on > CRAN to fit multivariate autoregressive state-space models using a > Kalman-filter approach. > > Cheers, > > Peter > > Péter Sólymos > Alberta Biodiversity Monitoring Institute > and Boreal Avian Modelling project > Department of Biological Sciences > CW 405, Biological Sciences Bldg > University of Alberta > Edmonton, Alberta, T6G 2E9, Canada > Phone: 780.492.8534 > Fax: 780.492.7635 > email <- paste("solymos", "ualberta.ca", sep = "@") > http://www.abmi.ca > http://sites.google.com/site/psolymos > > > > On Fri, Jul 23, 2010 at 1:02 PM, Kay Cichini <kay.cich...@uibk.ac.at> wrote: >> >> dear list, >> >> i searched though the archives and the question of repeated measure analysis >> with species data was often brought up but, as far as i found, never clearly >> worked out. >> >> if i have, say two time points at wich i sampled replicated plots and thus >> had replicated paired mutivariate obervations, how to deal with them >> properly. >> >> if i used adonis, to restrict permutations on the pairs of plots (as this >> would be done in an univariate permutation test for paired observations) >> does not make sense to me but i'm also dubious about neglecting the >> dependence of the pairing. >> >> any ideas would be highly appreciated, >> kay >> >> ----- >> ------------------------ >> Kay Cichini >> Postgraduate student >> Institute of Botany >> Univ. of Innsbruck >> ------------------------ >> >> -- >> View this message in context: >> http://r-sig-ecology.471788.n2.nabble.com/repeated-measures-with-multivariate-data-tp5330819p5330819.html >> Sent from the r-sig-ecology mailing list archive at Nabble.com. >> >> _______________________________________________ >> R-sig-ecology mailing list >> R-sig-ecology@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology >> >> > > _______________________________________________ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology _______________________________________________ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology