I remove only class "patient_centre2_female", then my
contrast would have 11 (-1) and 12 (1) as opposed to 12 and 12. Could
you please clarify?
Thanks again,
Colleen
Original Message --------
Subject: Re: [Freesurfer] FSGD design for multi-centre study
Date: 2018-04-20 11:19
From: &q
0.
>>> For instance if I remove only class "patient_centre2_female", then my
>>> contrast would have 11 (-1) and 12 (1) as opposed to 12 and 12. Could
>>> you please clarify?
>>>
>>> Thanks again,
>>> Colleen
>>>
>>> --
tive values would no longer add up to 0.
For instance if I remove only class "patient_centre2_female", then my
contrast would have 11 (-1) and 12 (1) as opposed to 12 and 12. Could
you please clarify?
Thanks again,
Colleen
Original Message --------
Subject: Re: [Freesurfer] FSGD
e contrast positive and negative values would no longer add up to 0.
>> For instance if I remove only class "patient_centre2_female", then my
>> contrast would have 11 (-1) and 12 (1) as opposed to 12 and 12. Could
>> you please clarify?
>>
>> Thanks again,
se clarify?
>
> Thanks again,
> Colleen
>
> ---- Original Message ----
> Subject: Re: [Freesurfer] FSGD design for multi-centre study
> Date: 2018-04-20 11:19
> From: "C.P.E. Rollins"
> To: Freesurfer
>
> Thanks a lot for the explanation. The issue is that
and 12 (1) as opposed to 12 and 12. Could
you please clarify?
Thanks again,
Colleen
Original Message
Subject: Re: [Freesurfer] FSGD design for multi-centre study
Date: 2018-04-20 11:19
From: "C.P.E. Rollins"
To: Freesurfer
Thanks a lot for the explanation. The i
Just remove the class.
ps. Please remember to include previous correspondences so we have context
On 4/20/18 6:19 AM, C.P.E. Rollins wrote:
> External Email - Use Caution
>
> Thanks a lot for the explanation. The issue is that I don't think
> Freesurfer will run a design for which there
External Email - Use Caution
Thanks a lot for the explanation. The issue is that I don't think
Freesurfer will run a design for which there are no subjects for a given
class. So if I keep the classes (24 classes since 6 centres x 2 gender x
2 groups (patient vs. control), and ha
sorry for the delay ...
You will definitely need to change the contrast values so that the
positives and negatives both add to the same number (with opposite
sign). It is a bit of a judgement call in terms of removing them
entirely. With an unbalanced design, you cannot remove the fixed effect
Hi,
I just wanted to ask again regarding my question below.
I've noticed that 2 of the centres contribute a smaller number of
subjects and don't in fact have any female controls. Should I remove
these as classes (ie. take out control_Female_centre1 and
control_Female_centre2) and then change t
Thanks for your help. I've noticed, however, that 2 of the centres
contribute a smaller number of subjects and don't in fact have any
female controls. Should I remove these as classes (ie. take out
control_Female_centre1 and control_Female_centre2) and then change the
subsequent contrast file t
That looks right to me. If you use a DOSS model and have a lot of
subjects, I don't think there should be a problem with so many classes.
On 04/09/2018 09:50 AM, C.P.E. Rollins wrote:
> Hi Douglas,
>
> Thanks for your response. I just wanted to confirm how the FSGD and
> contrast files might loo
Hi Douglas,
Thanks for your response. I just wanted to confirm how the FSGD and
contrast files might look for the multicentre study. If I'm to create a
separate class for each combination of diagnosis, sex, and center, would
there then be 24 classes? (as there are 2 diagnoses (patient vs.
cont
Create a separate class for each combination of diagnosis, sex, and
center, then create contrasts that average over center.
On 4/6/18 7:11 AM, C.P.E. Rollins wrote:
> Dear Freesurfer Developers,
>
> I'd like to do a standard CT analysis (patients vs. controls, covaried
> for age and sex) on data
Dear Freesurfer Developers,
I'd like to do a standard CT analysis (patients vs. controls, covaried
for age and sex) on data from a multi-centre study and I'm wondering how
I should construct my FSGD file to code centre as a dummy variable.
Currently, my FSGD looks something like this:
GroupDesc
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