nlme package, fixing variance.covariance matrix of residuals
This is an indirect (non)-answer, but Wolfgang Viechtbauer has a nice comparison of lme and rma in the metafor online documentation: http://www.metafor-project.org/doku.php/tips:rma_vs_lm_lme_lmer It might be possible to figure out your problem from that -- and if you do, please 'self-answer' on the list to document it for other users! Best, Phillip
On 08/17/2017 07:09 PM, W?lwer, Anna-Lena wrote:
Dear R team, I would like to do a multivariate meta-analysis in R using the nlme package. In meta-analysis I fix the residuals to known sampling errors. As I do a multivariate analysis, I have a variance-covariance matrix of sampling errors. Unfortunately, via varFixed I can only fix a vector of sampling errors and no matrix. In the R package metafor using the rma.mv function I can insert the variance-covariance matrix in the function. I would like to do the same with lme from the nlme package as nlme provides more flexibility for my model. Do you now any possibility of doing so in nlme? Are there any changes planned to incorporate this feature? Best wishes, I am looking forward to your feedback Anna-Lena W?lwer [[alternative HTML version deleted]]
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