[R-meta] rma.glmm model selection

[Philippe Tadger]

Thank you very much Wolfgang for this additional option in rma.glmm, I 
was not aware.


On 12/09/2021 23:36, Viechtbauer, Wolfgang (SP) wrote:
> I would say that if the log likelihoods are not meaningfully comparable, then neither are the AIC or BIC values.
>
> Speaking of these different models, in the 'devel' version of metafor, rma.glmm() now even allows for even more flexibility:
>
> https://wviechtb.github.io/metafor/reference/rma.glmm.html
>
> See especially the 'Note' section. One can now control the coding of the group variable and for "UM.RS" one can now allow for correlation between the random study effects and the random group effect (just as a side-note, to make our lives even more complicated having to choose among an even wider collection of potential modeling options).
>
> Best,
> Wolfgang
>
>> -----Original Message-----
>> From: Philippe Tadger [mailto:philippetadger using gmail.com]
>> Sent: Sunday, 12 September, 2021 22:54
>> To: Viechtbauer, Wolfgang (SP); r-sig-meta-analysis using r-project.org
>> Subject: Re: [R-meta] rma.glmm model selection
>>
>> Hello Wolfgang, colleagues
>>
>> Thanks for the answer!
>>
>> I've been reading the article  (Jackson et al., 2017) were you explain such models
>> and provide codes for SAS/Stata/R.
>> I did run the SAS code with the sham data, and collect all goodness of fit for
>> models 2-6
>>
>>          AIC   BIC   -2 x Likelihood   Model Name                          effects
>> Variance-covariance Matrix Other name
>> Model 4  80.74 80.25 62.74             modified Simmonds and Higgins model Fixed
>> UM.FS
>> Model 2  81.53 81.05 63.53             Simmonds and Higgins model          Fixed
>> Model 5  91.19 90.97 83.19             modified Simmonds and Higgins model Random
>> CV                         UM.RS
>> Model 6  93.18 92.91 83.18             Van Houwelingen bivariate model     Random
>> UN                         CM.AL
>> Model 3  93.76 93.54 85.76             Simmonds and Higgins model          Random
>> CV
>>
>> I understand that the likelihood measure can not be used if the distributions or
>> models are not nested (models 6 & 7 or CM.AL and CM.EL), which is not the case as
>> you point it out.
>> Do you consider the AIC values also not "meaningful" to choose between models?
>>
>> Sorry if there's is any typo in the self made table (trying to unify all the names
>> and features of each model)
>>
>> Thanks in advance for you valuable time
>>
>> On 12/09/2021 15:00, Viechtbauer, Wolfgang (SP) wrote:
>> Hi Philippe,
>>
>> Good question. I doubt that a direct comparison of the likelihoods of these models
>> (or information criteria) is meaningful though. For example, UM.FS and UM.RS
>> differ both in terms of their fixed and random effects (since the whole point is
>> to use either fixed or random study effects). CM.AL and CM.EL differ even more
>> fundamentally, as they use other distributions.
>>
>> The sentence that you quote is true, but the devil is, as always, in the details.
>> Here, I was thinking more in terms of: We have some specific model where we can
>> swap in or out certain random effects. Once you start swapping in and out fixed
>> and random effects at the same time and even switching distributions, then things
>> get a lot more tricky.
>>
>> So, I really don't have any good suggestions at the moment.
>>
>> Best,
>> Wolfgang
>>
>> -----Original Message-----
>> From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org] On
>> Behalf Of Philippe Tadger
>> Sent: Saturday, 11 September, 2021 12:42
>> To: r-sig-meta-analysis using r-project.org
>> Subject: [R-meta] rma.glmm model selection
>>
>> Dear Meta community
>>
>> I would like to ask for guidance on  how to do model selection in
>> metafor::rma.glmm. I'm thinking specifically in the comparison between:
>> UM.FS, UM.RS, CM.AL, CM.EL methods. Is it possible to conduct a goodness
>> of fit or alternative selection methods between the 4 models?
>>
>> I saw the model selection here
>> https://www.metafor-
>> project.org/doku.php/tips:model_selection_with_glmulti_and_mumin
>> <https://www.metafor-
>> project.org/doku.php/tips:model_selection_with_glmulti_and_mumin>
>> for predictors that mention that is possible to do a similar approach
>> with rma.glmm. Also a specific phrase catch my attention: "one can also
>> consider model selection with respect to the random effects structure."
>>
>> Thanks in advance for your help and time
>>
>> --
>>
>> Kind regards/Saludos cordiales
>> *Philippe Tadger*
>> ORCID <https://orcid.org/0000-0002-1453-4105>, Reseach Gate
>> <https://www.researchgate.net/profile/Philippe-Tadger>
>> Phone/WhatsApp: +32498774742
-- 
Kind regards/Saludos cordiales
*Philippe Tadger*
ORCID <https://orcid.org/0000-0002-1453-4105>, Reseach Gate 
<https://www.researchgate.net/profile/Philippe-Tadger>
Phone/WhatsApp: +32498774742

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