[R-meta] [netmeta] Error message in network meta-analysis: "Problem with multi-arm studies: Studies with inconsistent treatment estimates"

[Viechtbauer, Wolfgang (SP)]

Dear Rebecca,

studlab treat1 treat2        TE        resid
       34     PE    SIT -0.144613  0.00143599
       34     PE     WL -1.855309 -0.00143599
       34    SIT     WL -1.706388  0.00143599

If  PE - WL = -1.855309
and
if SIT - WL = -1.706388
then PE - SIT = -1.855309 - -1.706388 = -0.148921, but you have -0.144613, which is off by -0.004308. Since the default value for argument 'tol.multiarm' is 0.001, you will get an error.

Best,
Wolfgang

>-----Original Message-----
>From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org]
>On Behalf Of Rogasch, Rebecca Manuela Madeleine
>Sent: Friday, 21 February, 2020 19:54
>To: Guido Schwarzer; r-sig-meta-analysis using r-project.org
>Subject: Re: [R-meta] [netmeta] Error message in network meta-analysis:
>"Problem with multi-arm studies: Studies with inconsistent treatment
>estimates"
>
>Dear experts,
>
>first of all, I want to thank you again for your help!
>
>I am very thankful and really appreciate that you took time to answer my
>Questions.
>
>Dear Gerta R�cker, I apologize for the late Response, your Reply in the
>Mailing list hadn't reached me for some reason
>
>but was forwarded to me now.
>
>The Problem is Pretty much solved after entering the data in the Format you
>suggested.
>
>I no longer get an error for any of the nine 3-arm-studies, except for one -
>study "34".
>
>Output when applying "details.chkmultiarm":
>
>Multi-arm studies with inconsistent treatment effects:
>studlab treat1 treat2        TE        resid
>       34     PE    SIT -0.144613  0.00143599
>       34     PE     WL -1.855309 -0.00143599
>       34    SIT     WL -1.706388  0.00143599
>Legend:
>resid - residual deviation (observed minus expected)
>TE - treatment estimate
>
>I checked the data that I entered many, many times and compared it to the
>values in the paper.
>
>The values are correct, the data structure should be correct now.
>
>I am puzzled  - and feeling a bit uncomfortable asking this last Question.
>
>But I am hoping that someone has an Explanation?
>
>Best regards,
>
>Rebecca