Dear users, I'm trying to implement the nonparametric "two-stage" bootstrap (Davison and Hinkley 1997, pag 100-102) in R. As far as I understood, 'bootcov' is the most appropriate method to implement NONPARAMETRIC bootstrap in R when you have clustered data (?). I read the 'bootcov' manual but I still have a few questions: 1 - When the variable 'cluster' is introduced, then only clusters will be resampled (with replacement)? 2 - I can implement 'two-stage' bootstrap in STATA by running bootstrap sampling on top of the bootstrap command. Example: bootsrap cost, cluster(group): bsampling cost treat This means that in the 1st stage I resample clusters (with replacement) and then resample individuals within those clusters. I wonder whether we could do a similar procedure in R, i.e. if it is sensible to do something like: f<-boot(cost~treat) mod<-bootcov(f, cluster, B=1000, coef.reps=TRUE) Do you have any other ideas? Do I need to define 'fitter'? Thanks a lot, Manuel Gomes -- View this message in context: http://n4.nabble.com/Bootcov-for-two-stage-bootstrap-tp1819605p1819605.html Sent from the R help mailing list archive at Nabble.com.