[R] robumeta package - error

Michael Dewey
Fri, 02 Sep 2016 11:01:04 -0000

Dear Kristina

I do not use that package so cannot offer any direct help but

1 - can you fit the model with any other combination of parameters?
2 - what happens if you vary rho?
3 - if your data-set is small and not confidential can you share it,
otherwise can you show us str(anxiety_control) or
summary(anxiety_control) preferable without any variables you are not
using in this model?
4 - there is a robust option in Wolfgang Viechtbauer's metafor package
which might help although I am not sure how equivalent the analysis
approaches are.

On 01/09/2016 17:52, Kristina Loderer wrote:
> Dear all,
>
> I am trying to fit a simple (intercept-only) meta-analytic model using
> the robumeta package using the following code:
>  anx_cont_mean<-robu(formula = es_fisher ~ 1, var.eff.size >
variance_fisher, studynum = study_ID, modelweights = "CORR", rho =
0.8,
> small=TRUE, data = anxiety_control)
>
> When I try to run this model, the following error message pops up:
> Error in solve.default(sumXWX) :
>   system is computationally singular: reciprocal condition number = 0
>
> What exactly does this mean in the context of meta-analysis? I haven't
> been able to find any answers.
>
> Thank you,
> Kristina
>
>
> -----------------------------------------
> Kristina Loderer
> Ludwig-Maximilians-Universit?t M?nchen
> Department Psychologie
> Leopoldstr. 13
> D-80802 M?nchen
>
> Telefon: +49 (89) 2180-6047
> Email: Kristina.Loderer at psy.lmu.de
>
> -----------------------------------------
>
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--
Michael