Hi I am trying to run a mixed effects model taking into account that i sampled in the same locations four times i.e. temporal repeated measures. From what i gathered i need to group my data by my repeated measure - time - and state the structure of my random variables so i tried this: mixedmodel<-groupedData(response~time|randoma/randomb/subj, outer=~fixeda+fixedb+fixedc+fixedd+fixede+fixedf, mixedmodel) This went through ok and then i tried running the model: mixmod1<-lme(reponse~fixeda+fixedb+fixedc+fixedd+fixede+fixedf, data=mixedmodel, random=~time|randoma/randomb/subj) I got there error term: Error in na.fail.default(list(time= c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, : missing values in object There are no missing values in my time factor but taking out any NAs which were in my data elsewhere i ran again and got: Warning message: Fewer observations than random effects in all level 3 groups Subj was a factor i made by numbering each of my samples to represent the lowest unit. I wondered if the reason i didnt have enough observations was becasue i was working right down to my lowest unit so i took out subject from my data grouping and model and tried again and got: Error in logLik.lmeStructInt(lmeSt, lmePars) : NA/NaN/Inf in foreign function call (arg 3) In addition: There were 50 or more warnings (use warnings() to see the first 50) I am new to both R and mixed models so am pretty lost as to where to go next from here. Any help or suggestions would be greatly appreciated. Thankyou in advance -- View this message in context: http://www.nabble.com/Grouping-Data-for-Repeated-Measure-Mixed-Model-tf4770208.html#a13644765 Sent from the R help mailing list archive at Nabble.com.