Dear Thomas Lumley, and R-help list members, I have read your article "Network meta-analysis for indirect treatment comparisons" (Statist Med, 2002) with great interest. I found it very helpful that you included the R code to replicate your analysis; however, I have had a problem replicating your example and wondered if you are able to give me a hint. When I use the code from the article:
lme1 <- lme(Y1 ~ trt.B + trt.C + trt.D + trt.E, random = ~ 1 | trtpair, data=lumley1, var = varConstPower(form=~sigma, fixed=list(power=1))) I get an error message: Error in lme(Y1 ~ trt.B + trt.C + trt.D + trt.E, random = ~1 | trtpair, : unused argument(s) (var = list(const = numeric(0), power = numeric(0))) The problem seems to be in the varConstPower component, but I don't understand exactly what is wrong. (I have pasted the complete code to reproduce the result at the end of this email.) I use R 2.6.1 and nlme 3.1-86. Any help would be greatly appreciated! Best, Christian Gold ------- lumley1 <- scan() 2 1 -2.428 -1.451 2 5 3.233 3.819 3 2 -0.493 -0.405 1 2 0.577 1.868 3 1 -2.06 -0.709 3 4 1.976 1.196 2 3 1.084 2.055 2 3 1.255 1.278 3 4 0.807 1.058 3 4 0.254 1.672 1 4 3.008 3.634 1 5 3.817 4.063 2 1 -0.755 -0.405 1 3 1.339 2.100 lumley1 <- data.frame(matrix(lumley1, byrow=T, ncol=4)) names(lumley1) <- c("Active", "Control", "Y1", "Y2") trt <- matrix(0, ncol=5, nrow=nrow(lumley1)); colnames(trt) <- paste("trt", LETTERS[1:5], sep=".") for (i in 1:nrow(trt)) {trt[i, lumley1$Active[i]] = 1; trt[i, lumley1$Control[i]] = -1} lumley1 <- data.frame(data.frame(trt), lumley1) lumley1 <- transform(lumley1, trtpair = paste(Active, Control)) sigma <- rep(sqrt(.5), nrow=lumley1) library(nlme) lme1 <- lme(Y1 ~ trt.B + trt.C + trt.D + trt.E, random = ~ 1 | trtpair, data=lumley1, var = varConstPower(form=~sigma, fixed=list(power=1))) summary(lme1) lme2 <- lme(Y2 ~ trt.B + trt.C + trt.D + trt.E, random = ~ 1 | trtpair, data=lumley1), var = varConstPower(form=~sigma, fixed=list(power=1))) summary(lme2) ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.