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R-sig-mixed-models Digest, Vol 15, Issue 23

Iasonas Lamprianou 
Prof. Bates,
we all thank you for investing so much time to write the book (Multilevel models in R). A polite request: please, please include as many practical and detailed examples as possible, Not just one example per chapter. And what we need, is detailed guides on how to interpret the results. And how to defend our models: i.e. to prove that they have satisfactory fit and that we have not violated their assumptions.
Thanks
 
Dr. Iasonas Lamprianou
Department of Education
The University of Manchester
Oxford Road, Manchester M13 9PL, UK
Tel. 0044 161 275 3485
iasonas.lamprianou at manchester.ac.uk


----- Original Message ----
From: "r-sig-mixed-models-request at r-project.org" <r-sig-mixed-models-request at r-project.org>
To: r-sig-mixed-models at r-project.org
Sent: Friday, 28 March, 2008 1:00:02 PM
Subject: R-sig-mixed-models Digest, Vol 15, Issue 23

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Today's Topics:

  1. Re: New alpha version of lme4 code on R-forge (Douglas Bates)
  2. use of pedigree structures (ian white)
  3. Re: use of pedigree structures (Douglas Bates)
  4. Re: how to locate standard errors in lmer output (Douglas Bates)


----------------------------------------------------------------------

Message: 1
Date: Thu, 27 Mar 2008 08:17:59 -0500
From: "Douglas Bates" <bates at stat.wisc.edu>
Subject: Re: [R-sig-ME] New alpha version of lme4 code on R-forge
To: "Dan Wright" <danw at sussex.ac.uk>
Cc: R Mixed Models <r-sig-mixed-models at r-project.org>
Message-ID:
    <40e66e0b0803270617v4bd360a6j9987e01f005a9a27 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
On Thu, Mar 27, 2008 at 4:30 AM, Dan Wright <danw at sussex.ac.uk> wrote:
Thanks for the inquiry.  The working title of the book is "Multilevel
modeling in R" although that may change before publication.  It is on
the practice of using the lme4 package to fit and analyze
mixed-effects models, including linear mixed models, generalized
linear mixed models, nonlinear mixed models and generalized nonlinear
mixed models.  I emphasize graphical displays of the data and aspects
of the fitted models and inferences based on MCMC samples from the
posterior distribution of the model parameters.  The statistical
theory and computational methods for fitting and analyzing the models
are also described in detail.

I have given up on issuing predictions of when the book will be
available.  "Not soon" is about the best I can say.  There is a lot of
writing still to be done.  Thanks for the suggestion of citing the
book when using lme4 but that would be premature.



------------------------------

Message: 2
Date: Thu, 27 Mar 2008 12:40:48 +0000
From: ian white <i.m.s.white at ed.ac.uk>
Subject: [R-sig-ME] use of pedigree structures
To: r-sig-mixed-models at r-project.org
Message-ID: <47EB95D0.3070602 at ed.ac.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

The lmer function includes random terms as

(expression for a model matrix|grouping factor)

and I wonder how general the expression can be. For example, a pedigree 
object can be converted to an A matrix (in the language of animal 
breeding), but can the A matrix be incorporated into an lmer analysis?

I thought that

(chol(pedigree)|ones)

might be OK, where 'ones' is a constant vector of value 1. With the only 
example I have tried, the syntax is accepted but the analysis ends with 
a forced exit from R (core dump).