[R-meta] Effect size using forest plot

Viechtbauer, Wolfgang (SP) wolfg@ng@viechtb@uer @ending from m@@@trichtuniver@ity@nl
Thu Dec 13 17:08:32 CET 2018

Please always include the mailing list in replies.

Not sure what you mean by "not encouraging". But regardless, see help(escalc):

The options for the measure argument are then:

- "ARAW" for raw alpha values.
- "AHW" for transformed alpha values (Hakstian & Whalen, 1976).
- "ABT" for transformed alpha values (Bonett, 2002).

So, use measure="ARAW".


>-----Original Message-----
>From: Julie Webbs [mailto:webbsjulie using gmail.com]
>Sent: Thursday, 13 December, 2018 17:03
>To: Viechtbauer, Wolfgang (SP)
>Subject: Re: [R-meta] Effect size using forest plot
>Hakstian & Whalen is not encouraging for me. you stated:  One can meta-
>analyze raw alpha values, Can I ask How?
>On Thu, Dec 13, 2018 at 3:58 PM Viechtbauer, Wolfgang (SP)
><wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
>Now that is a rather different case. Search help(escalc) for "Cronbach's
>alpha". Here, one needs to specify the observed alpha values, the number
>of items/replications/parts of the measurement instrument, and the sample
>sizes. One can meta-analyze raw alpha values, but it is usually better to
>apply a transformation, like those described by Hakstian & Whalen (1976)
>Bonett (2002).
>>-----Original Message-----
>>From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-
>>project.org] On Behalf Of Gerta Ruecker
>>Sent: Thursday, 13 December, 2018 16:53
>>To: Julie Webbs; R meta
>>Subject: Re: [R-meta] Effect size using forest plot
>>Do the Cronbach's alpha values have a standard error?
>>Am 13.12.2018 um 16:48 schrieb Julie Webbs:
>>> Yes as an exampel. Some times we have a single value, e.g, Cronbach's
>>> alpha
>>> On Thu, Dec 13, 2018 at 3:39 PM Gerta Ruecker
>>> <ruecker using imbi.uni-freiburg.de <mailto:ruecker using imbi.uni-freiburg.de>>
>>> wrote:
>>>     You mean a mean without SD or sample size? Perhaps I still do not
>>>     understand what you have.
>>>     Best,
>>>     Gerta

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