Treatment effect proportional to time
SECONDARY
We now begin to address our primary aim: to estimate the power of the random slopes model, in the first instance when there is a proportional treatment effect in the trial. We also look at the performance of our other two analysis models for our secondary aim.Firstly, the empirical power for the steady decline trajectory and random slopes model is indeed close to the 80% power used in the sample size calculation, for both a 5-year and a 3-year trial (Fig. Powers for trials with a proportional treatment effect and smaller residual error variance. Left-hand panel: 5-year trial. Right-hand panel: 3-year trial. Ranges plotted are For a 5-year trial, all models and mean trajectories have treatment effects close to that expected (Figure A6.2.1, For a 3-year trial (right-hand panel of Fig. Some insight into this result can be gained by looking at the sample sizes specified by the observational study for the 5-year and 3-year trials (Fig. 