[R-meta] How to Get PIs for Moderator Analyses

Michael means using the profile() function.

This aside, if you use predict(<model>), then it will compute predicted/fitted values based on the model matrix (and corresponding CIs/PIs). If you want predicted values for particular combinations of moderator values, then you have to specify the 'newmods' argument.

Best,
Wolfgang

-----Original Message-----
From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces at r-project.org] On
Behalf Of Tori Pe?a via R-sig-meta-analysis
Sent: Tuesday, 13 June, 2023 19:51
To: Michael Dewey
Cc: Tori Pe?a; R Special Interest Group for Meta-Analysis
Subject: Re: [R-meta] How to Get PIs for Moderator Analyses

Hi Michael,

Thanks for your response!  What do you mean by profiling the variance?
Yes, some of my moderators had virtually no effect in our models.  I have
the issue with the PI being displayed for each data point in the model
instead of the PI for the model across all the moderators, unfortunately.

On Tue, Jun 6, 2023 at 12:20?PM Michael Dewey <lists at dewey.myzen.co.uk>
wrote:

Dear Tori

It might help to know exactly why you think the ouput is incorrect but I
notice that (a) your random effects seem to have very small variances
(have you tried profiling them?) (b) your moderator does not seem to
have much effect either.

Michael

On 06/06/2023 16:59, Tori Pe?a via R-sig-meta-analysis wrote:

Hello Listserv -

I wanted to know if folks know of a way to get prediction intervals for
moderator analyses!  I tried the predict() function but the output looks
incorrect.  I attached a screenshot below of the code plus a part of the
output.

Thanks in advance!

--
*Tori Pe?a, Ph.D. *(she/her/ella)
Cognitive Psychology
Dept. of Psychology
Stony Brook University
Stony Brook, NY 11790-2500
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