search for: catgeorical

...)*factor(Grade), random=~Schoolid+Teacherid+Studentid, family="categorical", data=data[data$Grade>=4,]) Error in MCMCglmm(FCATprofLevel ~ transferTypeCat + factor(yr >= 2008) + : please use idh(trait):units, us(trait):units or trait:units for error structures involving catgeorical data with more than 2 categories Does anyone know how I can fix it? Thanks -- View this message in context: http://r.789695.n4.nabble.com/How-to-write-random-effect-in-MCMCglmm-tp3567056p3567056.html Sent from the R help mailing list archive at Nabble.com.