Treatment effect not proportional to time
We now assess the power of our analysis models in the presence of a treatment effect that is either proportional to control group arm change or delayed decline.For a 5-year trial, the random slopes model and the linear trajectories, free covariance model both have substantially different final time-point treatment effects (as converted from a difference in slopes between the treatment groups) to those expected (Fig. 5-year trials with non-proportional treatment effects and smaller residual error variance. Left-hand panel: mean treatment effect at 5 years, converted from differences in slopes between the treatment groups for the random slopes and linear trajectories, free covariances models. Right-hand panel: power. Ranges are These issues are exacerbated when the length of the trial is 3 years (Fig. 3-year trials with non-proportional treatment effects and smaller residual error variance. Left-hand panel: mean treatment effect at 3 years, converted from differences in slopes between the treatment groups for the random slopes and linear trajectories, free covariances models. Right-hand panel: power. Ranges are 