Larger residual error variance, 
The patterns of results for the scenarios with a larger residual error variance were often similar to those for the smaller residual variance. The Type I error for the random slopes model for an early decline trajectory and a 3-year trial was no longer conservative (Table A7.1.2, For a proportional treatment effect, the power of the random slopes model was close to 80% for all mean trajectories for both 3- and 5-year trials (Figures A7.2.1 and A7.2.2, Again, some insight into this result can be gained by looking at the sample sizes specified by the observational studies. The sample sizes specified for a 3-year trial and non-linear trajectories are closer to those for the steady decline trajectory for the larger residual variance scenarios than in the corresponding scenarios with a smaller residual variance (Fig. When using a non-proportional treatment effect with the larger residual variance, the power is again not at nominal levels for all mean trajectories and analysis models for a 5-year trial. However, for all mean trajectories except late decline the treatment effect for the random slopes model is over-estimated, leading to greater than nominal power levels (Figure A7.3.1, 