Dear Martyn,
Thanks for sharing your paper, that was quick - I'm sure it could be
published as a technical note in another journal, at least you have a
DOI now (no, I was not a reviewer).
Our usual citation is the Henson&Penny book chapter you refer to:
http://www.fil.ion.ucl.ac.uk/~wpenny/publications/rik_anova.pdf
and Will wrote more recently some practical examples on how to implement
the partitioned error approach:
https://en.wikibooks.org/wiki/SPM/Group_Analysis
There's room for improvements though and feedbacks are welcome on what
is missing/unclear.
The code attached to the post below was also meant to facilitate the
practicalities of specifying several models by introducing a new option
in the batch interface for partitioned models:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=spm;7077f17d.1603
Rik's more recent book chapter is also an interesting read:
http://www.mrc-cbu.cam.ac.uk/wp-content/uploads/2015/03/Henson_EN_15_ANOVA.pdf
Now, for Karina's question: it's a 2x2 within-subject design so
everything can be tested with a simple one-sample t-test. Form the
contrasts of interest at the first level ([1 1 1 1], [1 1 -1 -1], [1 -1
1 -1] and [1 -1 -1 1]) and enter each of them in a separate one-sample
t-test. That's the partitioned error approach. For the pooled error
approach, you would proceed with the flexible factorial design and
specify a main effect of factor 1 and an interaction with factors 2 and
3. The contrast for the time by self interaction would then be [1 -1 -1
1 0 ... 0].
Best regards,
Guillaume.
On 11/04/18 12:14, Martyn Mcfarquhar wrote:
> Dear Samantha,
>
>
>
> Thank you very much. The paper is now available as a preprint on
> PsyArXiv for anyone who wishes to read it: https://psyarxiv.com/a5469
>
>
>
> Best wishes
>
> Martyn
>
>
>
> -------------------------------------------------
>
> Martyn McFarquhar, PhD
>
> Lecturer in Neuroimaging
>
> G30 Zochonis Building
>
> The University of Manchester
>
> Brunswick Street
>
> Manchester
>
> M13 9GB
>
>
>
> +44 (0)161 306 0450
>
> -------------------------------------------------
>
>
>
>
>
> *From: *Samantha Brooks <[log in to unmask]>
> *Date: *Wednesday, 11 April 2018 at 10:10
> *To: *Martyn Mcfarquhar <[log in to unmask]>
> *Cc: *"[log in to unmask]" <[log in to unmask]>
> *Subject: *Re: [SPM] 2 x 2 Repeated measures ANOVA
>
>
>
> Dear Martyn,
>
>
>
> Your aforementioned paper would indeed be an asset to the imaging
> community - we too are having various discussions about modeling a
> complex ANOVA at first level in SPM.
>
>
>
> Looking forward to reading your paper,
>
>
>
> Best regards,
>
>
> Samantha
>
>
> _______________
>
> Dr Samantha Brooks, Ph.D (Download
> Website)<http://www.drsamanthabrooks.com/>
>
> Dept. of Psychiatry,
>
> J2 Building, Groote Schuur Hospital
>
> Anzio Road
>
> Observatory
>
> Cape Town
>
>
>
> On Wed, Apr 11, 2018 at 10:51 AM, Martyn McFarquhar
> <[log in to unmask]<mailto:[log in to unmask]>>
> wrote:
>
> Hi Karina,
>
> Adding the main effects and interactions in the flexible factorial
> module only adds these effects to the design matrix, it doesn't
> create the contrasts for those effects. I'll discuss creating the
> contrasts separately below, but in terms of your design being a 2 x
> 2 fully within-subject, you will need multiple models to calculate
> the F-statistics using the correct error term. For instance, your
> effects are:
>
> Main effect of time: needs a model containing Time and Subject after
> averaging over Self
> Main effect of self: needs a model containing Self and Subject after
> averaging over Time
> Time x Self: needs a model containing Time, Self, Time x Self,
> Subject, Time x Subject and Self x Subject
>
> The contrasts are another matter because of the necessity of
> creating estimable functions of the parameters in overparameterised
> designs. In unbalanced designs this is particularly tricky given
> that most people are after the standard Type III sums-of-squares.
>
> Because this is such a common issue on the list, I have actually
> written a paper going over the how and the why of both of these
> issues, with an example in SPM. I submitted it to NeuroImage, but
> the reviewers came back stating that none of it was new and no one
> would find it useful. Not that I'm bitter, but it'd be nice to
> actually know that some people would find it useful! I'm planning to
> put it up as a preprint on arXiv, but I'll send you the current
> draft separately. I hope it will help answer your questions and help
> you understand what you need to do.
>
> Best wishes
> Martyn
>
> -------------------------------------------------
> Martyn McFarquhar, PhD
> Lecturer in Neuroimaging
> G30 Zochonis Building
> The University of Manchester
> Brunswick Street
> Manchester
> M13 9GB
>
> +44 (0)161 306 0450
> -------------------------------------------------
>
>
>
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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