Why don't you test it yourself? E.g., set.seed(42) bob1 <- rnorm(1000,0,1) set.seed(42) bob2 <- rnorm(500,0,1) bob3 <- rnorm(500,0,1) identical(bob1, c(bob2, bob3)) I won't tell you the answer. :-) -- Bjørn-Helge Mevik