Dear All, I would like to ask a question on the colour scheme I can specify for a plot(survfit.model). I have four lines of Drosophila, kept at 3 different temperatures. About 100 individuals per line and temperature were scored, no censoring. the data looks like: line temp day status line1 18 23 1 ..... My model (quite trivial) is like: surv.model<-survfit(Surv(day, status)~line+temp, mydata) My problem comes when I: plot(surv.model,col=1:4) The plot shows three main groupings, because temperature affects longevity in drosophila. The problem is that the colour used for "line1" at temperature "18C" is not the same for "line1" at temperature "28C", which I find extremely confusing. How can I specify to keep the same colour for the same line across the plot? regards, Federico Calboli -- ================================ Federico C. F. Calboli Dipartimento di Biologia Via Selmi 3 40126 Bologna Italy tel (+39) 051 209 4187 fax (+39) 051 251 4286 f.calboli at ucl.ac.uk