[R] mixed effects meta-regression: nlme vs. metafor

Christian Röver christian.roever at med.uni-goettingen.de
Wed Jan 23 14:23:04 CET 2013

Hi Wolfgang,

thanks for the instant and comprehensive reply!

On 01/23/2013 12:39 PM, Viechtbauer Wolfgang (STAT) wrote:
> [...]
> In fact, trying to disentangle that residual variance component from any random study effects is usually next to impossible. I mention this explicitly one more time, because I have seen some publications using lme() in exactly this way ...

I'm not too surprised -- it was only after some double-checking that I
noticed that variances are not actually fixed when using the "varFixed"

> [...]
> The updated version of the package still does not include that aforementioned function, but I may consider putting a pre-alpha version on the website so that the adventurous are able to try it out.

I'm looking forward to it...!

> Alternatively, you could try taking a look at MCMCglmm (http://cran.r-project.org/web/packages/MCMCglmm/index.html), which should be able to fit the model that you want. Can't give you any details on how, but if you get stuck, try posting to R-sig-mixed-models and Jarrod Hadfield (the MCMCglmm package author) is very likely to help you further.

Thanks; I was also thinking of switching to OpenBUGS + R2OpenBUGS, which
should provide the necessary flexibility at the price of some extra
complication... but having worked with it before, it should be doable...



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