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Re: st: Repeated measured analysis
From
Austin Nichols <[email protected]>
To
[email protected]
Subject
Re: st: Repeated measured analysis
Date
Wed, 10 Aug 2011 17:04:14 -0400
Marlis Gonzalez Fernandez <[email protected]>:
The suggestion was to use a cluster-robust standard error, used by
-svy- and -suest- and many other commands, which would normally be my
first thought as well. Unfortunately, with 13 clusters, the CRSE will
be severely biased downward.
Probably better with such a small sample size to analyze each type
separately, using a randomization/permutation test.
On Wed, Aug 10, 2011 at 1:30 PM, Marlis Gonzalez Fernandez
<[email protected]> wrote:
> Thank you Ronán-
>
> I agree looking not only at food but the interaction between food and disease will be really intresting...
>
> Thanks for the suggestions.
>
> Marlis
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Ronan Conroy
> Sent: Wednesday, August 10, 2011 12:15 PM
> To: [email protected]
> Subject: Re: st: Repeated measured analysis
>
> On 2011 Lún 10, at 16:44, Marlis Gonzalez Fernandez wrote:
>
>> Hello-
>>
>> Trying to help a colleague who has an interesting study.
>>
>> He has distance of movement (hyoid bone) measures in mm on 13 subjects with no less than 20 measures (some have many more than that) during swallowing 3 different foods (so lots of repeats!). He wants to determine if there are significant distance differences between normal and disease states (while taking into account food type). I was concerned about having so many repeated measures and appropriately accounting for that to discern where is the true variability (ie. disease state? Subject?). Any ideas welcome.maybe I am over-thinking this? Should he just analyze food types separately?
>
> Why not -svyset- with participant as the PSU?
>
> The interesting question was whether food type interacted with disease status. In achalasia, difficulty swallowing varies considerably by food type, and this may be true for other disorders of swallowing too - it's not my area - but I'd have a look at the interaction term.
>
>
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