thanks for your reply, Wolfgang!

Regarding the dots/circle -"problem" I am relieved now :-)

Regarding the Trim and Fill outcome I don't really think that it's the
wrong side, I just dont know how to interpret the result.

regtest () reveals a negative z, which is not significant.
ranktest () reveals a negative tau, which is not significant.

Any ideas? :-)

best,

Verena


On Mon, May 26, 2014 at 2:00 PM, Viechtbauer Wolfgang (STAT) <
wolfgang.viechtbauer@maastrichtuniversity.nl> wrote:

> From help(forest.rma):
>
> pch -- plotting symbol to use for the observed effect sizes or outcomes.
> By default, a solid circle is used. Can also be a vector of values. See
> points for other options.
>
> pch.fill -- plotting symbol to use for the effect sizes or outcomes filled
> in by the trim and fill method. By default, a circle is used. Only relevant
> when plotting an object created by the trimfill function.
>
> The defaults are pch=19 and pch.fill=21. So, by default, a solid circle is
> used for the observed outcomes and an open circle is used for the outcomes
> that are filled in.
>
> An example is shown here:
>
>
> http://www.metafor-project.org/doku.php/plots:funnel_plot_with_trim_and_fill
>
> From help(trimfill.rma.uni):
>
> side -- either "left" or "right", indicating on which side of the funnel
> plot the missing studies should be imputed. If left undefined, the side is
> chosen within the function depending on the results of Egger's regression
> test (see regtest for details on this test).
>
> The argument is left undefined by default, so the side is chosen based on
> the results of the regression test (essentially, whether the slope is
> positive or negative). If you think the suppression occurred on the other
> side than the one that is chosen, specify the side via this argument.
>
> Best,
> Wolfgang
> ________________________________________
> From: r-help-bounces@r-project.org [r-help-bounces@r-project.org] On
> Behalf Of Verena Weinbir [vweinbir@gmail.com]
> Sent: Monday, May 26, 2014 1:15 PM
> To: Michael Dewey
> Cc: r-help
> Subject: Re: [R] Metafor: Strange Trim and Fill Outcome?
>
> thanks for your reply, Michael!
>
> ad primary studies:
> yup, I have a large set of studies: At the moment I consider 126 data sets
> in my analysis.
>
> ad interpretation:
> thats an interesting information. But usually there should be found an
> effect.
>
> ad "bit" :-):
> I am irritiated, because in the plots I have studied so far, I always found
> that the observed studies are open circles and the additional "mirrored"
> effects are black dots. In my case, it is the other way round.
>
> Also, most of the mirrored circels appear in the right upper corner,
> indicating, that there are studies missing in my data set, which have
> smaller SDs (i.e. are more precise?) and higher effect sizes?
>
> best,
>
> Verena
>
> On Mon, May 26, 2014 at 12:26 PM, Michael Dewey <info@aghmed.fsnet.co.uk
> >wrote:
>
> > At 09:34 26/05/2014, Verena Weinbir wrote:
> >
> >> Hey guys,
> >>
> >> I have tested the metafor trim and fill function (y:SD, x:SMD)on my data
> >> set and yielded the following result:
> >>
> >> 1. missing studies on the right: 34
> >>
> > That seems a lot of missing studies unless you have a very large set of
> > primary studies.
> >
> >  2. open circles on the rights side appear to be the number of additional
> >> effects
> >>
> >> 3. adjusted d would be higher than observed d.
> >>
> > Implying that the mechanism is suppressing studies which found a large
> > effect. This might happen if the dominant view is that there is no effect
> > and so when people find one they worry about their results.
> >
> >  Since normally, as I understand, those parameters are the other way
> round
> >> (black dots indicating missing studies on the left, which would reduce
> the
> >> effect size), I wonder:
> >>
> >> Is there a mistake I have done? Or, if this is an actual outcome how
> can I
> >> interpret this?  That its not a publication bias that influences my data
> >> set, but a lack of precision (studies missing that are precise -small
> SD-
> >> and have big SMD)?
> >>
> > Sorry but that bit is not very clear to me.
> >
> >  Many thanks in advance!
> >>
> >> Verena
>

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