Multi-level (nested) correlation structures via geepack package
Hi Duncan, Thank you for your message. All of those citations and suggestions are wonderful and highly relevant for GEEs. My concern is that I need multi-level/nested correlation structures, whereas those handle the specification of covariance matrices at the level of repeated observations within-subject. I think the paper attached contains the theory behind such nested correlation structures, but the coding for it is not as apparent. Edward
?On 2020-07-12, 11:06 PM, "dulcalma dulcalma" <dulcalma at bigpond.com> wrote:
Hi
Your choice of package should partly depend on the type of dependent
variable or Y that you are going to be dealing with
categorical/ordinal data may involve different packages than continuous
or binary data see multgee for one.
The number of samples can also make a difference GEE with the "correct
model" should normally have no problems with numbers 30-40; 25 or less
would normally require corrections and a diffence package.
The doi for multgee paper is 10.1111/biom.12054 and Touloumis paper in
Journal of Statistical Software
For longitudinal data there is the following doi:
10.2307/2531248
and
10.1097/EDE.0b013e3181caeb90
10.1093/biomet/90.1.29
10.1007/s00362-017-0881-0
10.1002/sim.2368
a search for gee in the list of available packages should show you the
alternatives.
As a check of the result do the statistics on another package. I
remember doing a simple gee with an example
from a book using 4 different packages 2 of which gave poor or
unreasonable answers
Regards
Duncan
Duncan Mackay
Department of Agronomy and Soil Science
University of New England
ARMIDALE NSW 2351
------ Original Message ------
From: "Phat Chau" <phat.chau at mail.utoronto.ca>
To: "r-help at R-project.org" <r-help at R-project.org>; "sorenh at math.aau.dk"
<sorenh at math.aau.dk>
Sent: Sunday, 12 Jul, 2020 At 11:52 PM
Subject: Re: [R] Multi-level (nested) correlation structures via
geepack package
Hello,
I have a multi-level, cohort dataset with three levels: repeat measures
of a response (level 1), that are collected from individual participants
(level 2) who are students within a school (level 3). I would like to do
a generalized estimating equation (GEE) analysis of this clustered data,
but to do so I need to specify ?nested? correlation structures (e.g.
exchangeable, compound symmetric, Toeplitz) to account for the
within-individual and within-cluster correlations.
Here is a reference paper that describes a nested exchangeable
correlation structure and nested compound symmetry:
doi:10.1111/j.1541-0420.2009.01374.x.
The geepack is available in R to do GEE analyses, but it seems to me
that it only allows the user to specify a correlation structure via the
geepack(??corstr = ?) option which only accounts for the
within-individual correlations (that arise from repeated measures).
Would it be possible to specify the nested correlation structures that I
refer to here to also account for the within-cluster correlations using
this package?
Thank you,
Edward
______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.