[R-meta] "Favours experimental/vaccinated", "Favours control" - Metafor

[Michael Dewey]

I am sorry Andrzej but I really cannot think of anything which I would 
add to my explanation of how it works. When you look at the BCG data can 
you not see which direction the effect is going by examining tpos, tneg, 
cpos and cneg?

Michael

On 29/10/2023 17:24, Andrzej Andrzej wrote:
> Thank you Michael,
> Yes, I do not know how to quote here, but I try:
> 1. "Do you mean whether to type   c("Favors control","Favors experimental")
> or  c("Favors experimental", "Favors control")?"
> Yes, exactly I do mean that.
> 
> 
> 2. "If so the answer is that when you computed the effect size you knew
> whetheh high values favoured experimental and so would be on the right
> of the plot (the first option) or vice versa"
> Could you please guide me with explanation based on this code and WV 
> data, please:
> https://wviechtb.github.io/metadat/reference/dat.bcg.html 
> <https://wviechtb.github.io/metadat/reference/dat.bcg.html>
> 
> library(metafor)
> data(dat.bcg)
> dat <- dat.bcg
> 
> ### calculate log risk ratios and corresponding sampling variances
> dat <- escalc(measure="RR", ai=tpos, bi=tneg,
>                              ci=cpos, di=cneg, data=dat,
>                              slab=paste0(author, ", ", year))
> ### random-effects model
> res <- rma(yi, vi, data=dat)
> forest(res, addpred=TRUE, xlim=c(-16,7), at=seq(-3,2,by=1), shade="zebra",
>         ilab=cbind(tpos, tneg, cpos, cneg), ilab.xpos=c(-9.5,-8,-6,-4.5),
>         cex=0.75, header="Author(s) and Year")
> text(c(-9.5,-8,-6,-4.5), res$k+2, c("TB+", "TB-", "TB+", "TB-"), 
> cex=0.75, font=2)
> text(c(-8.75,-5.25),     res$k+3, c("Vaccinated", "Control"),   
>   cex=0.75, font=2)
> 
> 3. "whetheh high values favoured experimental and so would be on the right
> of the plot (the first option) or vice versa"
> Could you please explain using that forest plot and bcg.data, where are 
> those higher values (in which group) so how should I label Log Risk 
> Ratio X axis according to RevMan 5 style with " Favours control" and 
> "Favours vaccinated" ? I want to understand which way is correct, please.
> best regards,
> Andrzej
> 
> niedz., 29 paź 2023 o 17:15 Michael Dewey <lists using dewey.myzen.co.uk 
> <mailto:lists using dewey.myzen.co.uk>> napisał(a):
> 
>     Dear Andrzej
> 
>     Comment in line
> 
>     On 29/10/2023 15:30, Andrzej Andrzej via R-sig-meta-analysis wrote:
>      > Hi,
>      >
>      > I have a question about: "Favours experimental","Favours control" ?
>      >
>      > How do I do it correctly ?
>      >
>      > This is very easy for me to mix it up.
>      >
>      > https://www.metafor-project.org/doku.php/plots:forest_plot_bmj
>     <https://www.metafor-project.org/doku.php/plots:forest_plot_bmj>
>      >
>      > ### add 'Favours control'/'Favours experimental' text below the
>     x-axis
>      > text(c(-1,1), -2.5, c("Favors control","Favors experimental"),
>     pos=c(4,2),
>      > offset=-0.3)
>      >
>      > How do I do it, that this is not the other way around, please ?
>     And that my
>      > plot is correct and consistent with the data ?
> 
>     Do you mean whether to type   c("Favors control","Favors experimental")
>     or  c("Favors experimental", "Favors control")?
> 
>     If so the answer is that when you computed the effect size you knew
>     whetheh high values favoured experimental and so would be on the right
>     of the plot (the first option) or vice versa.
> 
>     Michael
> 
> 
> 
>      >    As a beginner in metafor I am able to easily mix it up like
>     this and now
>      > this is not reflecting the truth:
>      >
>      > text(c(-1,1), -2.5, c("Favours experimental", "Favours control"),
>      > pos=c(4,2), offset=-0.3)
>      > How do I know which way is correct ? In other words how do I know
>     where to
>      > place "Favours experimental" or "Favours Vaccinated" when I use
>     bcg data,
>      > left or right from 0 ?
>      >   I have done metafor::reporter(res) but still no clues in which
>      > direction/favour are the results/labels should be placed ?
>      >
>      > Is it possible to tweak reporter() function to show it ?
>      >
>      >
>      > Thank you very much in advance.
>      > regards,
>      > Andrzej
>      >
>      >       [[alternative HTML version deleted]]
>      >
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>     -- 
>     Michael
> 
> 
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Michael