[R] Adjusting confidence intervals for paired t-tests of multiple endpoints

Erich Studerus, Psychiatrische Uni-Klinik erich.studerus at bli.uzh.ch
Sun Mar 1 14:14:33 CET 2009

  Johannes Huesing <johannes at huesing.name> wrote:
> Couldn't you re-phrase your model by including timepoint as a continuous 
> regressor and scale as a factor?

Well, the measuring time points are 70 170, 300 and 1440 minutes after drug 
intake. Since the influence of time is cerainly not linear, I think it's 
better to treat it as categorical factor. In fact, I already calculated 
mixed effects models with the four-level factor time and the two-level 
factor treatment and random effects factors subjects (nested in studies) and 
studies for each scale. I used mixed effects models, because I'm doing a 
meta-analysis on the raw data of 8 studies. Thus my dataset has not only a 
grouping structure, but is also unbalanced (not all studies did 4 
measurements). I'm not sure, if I could extend my model by including another 
factor for scale, since these scales measure quite different things. I 
guess, It would be also very difficult the set up appropriate contrasts to 
compare each scale on each measuring time point.

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