[R-meta] Meta - Bug with REML or small N?

[Jorge Teixeira]

 Thanks Michael and Wolfgang.

Here goes the df:

structure(list(study = c("AA", "BB", "CC",
"EE", "DDD"), en = c(9, 41, 29, 8, 13
), em = c(32, 27.5, 28.7, 22.8, 30.5), esd = c(1.9, 3.8, 5.2,
3.8, 4.9), cn = c(8, 26, 28, 10, 14), cm = c(30.1, 24.9, 26.9,
24.7, 30.2), csd = c(2.4, 3.6, 3, 4.3, 5.1)), row.names = c(NA,
-5L), class = c("tbl_df", "tbl", "data.frame"))

Thanks


Michael Dewey <lists using dewey.myzen.co.uk> escreveu no dia terça, 21/03/2023
à(s) 16:36:

> Dear Jorge
>
> It looks as though the issue is that REML estimates tau^2 to be
> effectively zero whereas DL has a positive estimate. The different ways
> of estimating tau^2 do often differ, sometimes by quite surprising
> amounts. Whether that is related to the smallish number of studies I
> could not say but, at the moment, there does not seem to be evicence of
> anything wrong with the implementation of REML.
>
> Michael
>
> On 21/03/2023 14:57, Jorge Teixeira via R-sig-meta-analysis wrote:
> > Hi.
> >
> > Let me know if you need me to provide the data for this example.
> > Screenshots in the bottom.
> >
> > I ran this MA with REML, and the weight for random and common effects
> > are exactly the same! Never saw anything like this. t2values also don’t
> > look plausible.
> >
> > *_#1_*
> > vo2 <- metacont(en  , em, esd, cn, cm, csd, study, method.tau = "REML",
> > prediction = TRUE, data = dat_vo2, sm = "MD")
> > vo2
> >
> > Is this a bug or a particular issue of low number of studies and low
> > sample size?
> >
> > *_#2_*
> > vo2 <- metacont(en  , em, esd, cn, cm, csd, study, method.tau = "DL",
> > prediction = TRUE, data = dat_vo2, sm = "MD")
> > vo2
> >
> > I ran this with DL estimator and weights and t2are plausible. I also ran
> > other similar MA using REML and this was all okay.
> >
> > #1 using SMD instead of MD also looks fine.
> >
> >
> > Thanks,
> > Jorge
> >
> >
> > *_REML:_*
> >
> > image.png
> >
> >
> > *_DL:_*
> > image.png
> >
> >
> > <
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
> Virus-free.www.avg.com <
> http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient
> >
> >
> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> >
> > _______________________________________________
> > R-sig-meta-analysis mailing list @ R-sig-meta-analysis using r-project.org
> > To manage your subscription to this mailing list, go to:
> > https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis
>
> --
> Michael
> http://www.dewey.myzen.co.uk/home.html
>

	[[alternative HTML version deleted]]