Message-ID: <web-17839765@idmailbe2b.unizh.ch>
Date: 2009-03-01T13:14:33Z
From: Erich Studerus, Psychiatrische Uni-Klinik
Subject: Adjusting confidence intervals for paired t-tests of multiple endpoints
In-Reply-To: <20090301060450.GA9981@huesing.name>
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.