Dear all, Edmond Ng (http://multilevel.ioe.ac.uk/softrev/reviewsplus.pdf) provides an example to fit the mixed effects meta-analysis in Splus 6.2. The syntax is: lme(fixed=d~wks, data=meta, random=~1|study, weights=varFixed(~Vofd), control=lmeControl(sigma=1)) where d is the effect size, study is the study number, Vofd is the variance of the effect size and meta is the data frame.
"sigma=1" is required to constrain the level 1 variance in applying mixed-effects models in meta-analysis. In Splus 6.1, I found that the help manual of nlme includes "sigma" as an optional argument in lmeControl() to fix the within-group standard error during the optimization. However, both Pinheiro and Bates (2000, p.476) and the help manual of the nlme package in R for Version 3.1-65 (http://cran.r-project.org/doc/packages/nlme.pdf, p.172) do not include "sigma" as an argument for lmeControl(). I would like to know how I could fix the level-1 variances as known values in lme(). Thanks in advance! Best, Mike -- --------------------------------------------------------------------- Mike W.L. Cheung Phone: (852) 2857-8621 Department of Psychology Fax: (852) 2858-3518 The University of Hong Kong E-mail: [EMAIL PROTECTED] HONG KONG Website: http://web.hku.hk/~mikewlch ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html