[R-meta] specification of phi in vcalc
|uk@@z@@t@@|e|ow|cz @end|ng |rom un|-o@n@brueck@de
Wed Aug 3 17:14:27 CEST 2022
vcalc documentation contains a potentially helpful tip: "Argument phi
must then also be specified to indicate the autocorrelation among the
sampling errors of two effect sizes that differ by one unit on the time1
variable. As above, the autocorrelation of the measurements themselves
can be used here as a proxy."
Perhaps some tables in primary studies show correlations between
neighboring time points?
Another option: If raw data are available for some primary studies, then
one could estimate the correlation for several data sets and use it as
"phi" input for vcalc. If different data sets lead to different values,
then one could test different values in sensitivity analyses.
Institute for Psychology
Research methods, psychological assessment, and evaluation
49074 Osnabrück (Germany)
On 03.08.2022 12:00, r-sig-meta-analysis-request using r-project.org wrote:
> Send R-sig-meta-analysis mailing list submissions to
> r-sig-meta-analysis using r-project.org
> To subscribe or unsubscribe via the World Wide Web, visit
> or, via email, send a message with subject or body 'help' to
> r-sig-meta-analysis-request using r-project.org
> You can reach the person managing the list at
> r-sig-meta-analysis-owner using r-project.org
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of R-sig-meta-analysis digest..."
> Today's Topics:
> 1. specification of phi in vcalc (Danielle Hiam)
> Message: 1
> Date: Wed, 3 Aug 2022 06:54:48 +0000
> From: Danielle Hiam <danielle.hiam using deakin.edu.au>
> To: "r-sig-meta-analysis using r-project.org"
> <r-sig-meta-analysis using r-project.org>
> Subject: [R-meta] specification of phi in vcalc
> <ME3PR01MB54642B304670F1BF825E6F60B79C9 using ME3PR01MB5464.ausprd01.prod.outlook.com>
> Content-Type: text/plain; charset="iso-8859-1"
> I am running a meta-analysis that has nested data and dependent effect sizes (multiple timepoints). Therefore, I need to take into account effect sizes that are correlated and also cluster within studies. I will run vcalc, then the rma.mv function and then use robust with clubsandwich set to true to "correct" for any mis-specification of the model. However, I am looking for some clarification regarding how to "guess" the value for phi in the vcalc function, R code: V <- vcalc(FC_SD, cluster, time1=Time_NUM, data, phi=0.6).
> When I change phi from 0.6 to 0.8 in vcalc I get very different results from the meta-analysis (rma.mv followed by robust(.... Clubsanwich=T). I have read James Pustejovsky paper (DOI: https://doi.org/10.1007/s11121-021-01246-3) on this, where he suggests that in situations where no information is available, the meta-analyst might pick a plausible value and then conduct sensitivity analysis across a range reasonable values. How would I go about this?
> Any information regarding specification of phi would be greatly appreciated
> Deakin University
> Melbourne Burwood Campus, 221 Burwood Highway, Burwood VIC 3125
> danielle.hiam using deakin.edu.au
> Deakin University CRICOS Provider Code: 00113B
> Stay connected with IPAN
> Facebook Twitter
> Important Notice: The contents of this email are intended solely for the named addressee and are confidential; any unauthorised use, reproduction or storage of the contents is expressly prohibited.
> If you have received this email in error, please delete it and any attachments immediately and advise the sender by return email or telephone. Deakin University does not warrant that this email and any attachments are error or virus free.
> Important Notice: The contents of this email are intended solely for the named addressee and are confidential; any unauthorised use, reproduction or storage of the contents is expressly prohibited. If you have received this email in error, please delete it and any attachments immediately and advise the sender by return email or telephone.
> Deakin University does not warrant that this email and any attachments are error or virus free.
> Subject: Digest Footer
> R-sig-meta-analysis mailing list @ R-sig-meta-analysis using r-project.org
> To manage your subscription to this mailing list, go to:
> End of R-sig-meta-analysis Digest, Vol 63, Issue 1
More information about the R-sig-meta-analysis