[R-meta] converting escalc ROM outputs to the log-2 scale

Viechtbauer, Wolfgang (SP) wo||g@ng@v|echtb@uer @end|ng |rom m@@@tr|chtun|ver@|ty@n|
Sat Dec 12 00:37:52 CET 2020

Dear Divya,

If y_i ~ N(theta_i, v_i), then for any constant c, c*y_i ~ N(c*theta_i, c^2 * v_i).

So, it would be yi_new = yi/log(2) and vi_new = vi/log(2)^2.


>-----Original Message-----
>From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org]
>On Behalf Of Divya Ravichandar
>Sent: Friday, 11 December, 2020 23:36
>To: r-sig-meta-analysis using r-project.org
>Subject: [R-meta] converting escalc ROM outputs to the log-2 scale
>Hi all
>I have a question around changing the scale of *yi *and *vi *exported
>from *escalc()
>*function when using *measure=ROM.* Based on the documentation, this
>function exports *yi *in natural log (ln) scale. --> yi =
>ln(grp1-mean/grp2-mean) and then the associated vi.
>I am interested in obtaining the *log-2 fold change. *Is there a way to
>convert yi & vi from *escalc(measure = ROM,...) *to this scale. Would it be
>reasonable to simply transform the values by converting from log-e -> log-2
>scale by
>yi_new = yi/log(2) and vi_new = vi/log(2)
>Thank you
>*Divya Ravichandar*
>Second Genome

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