<p>Multiple methods were developed to estimate saved time to better interpret benefits of drugs in trials for Alzheimer’s disease. These methods include the backward projection methods by using the placebo disease progression curve estimated with the linear interpolation method or the spline method that connects the estimated mean values between the outcome changes over time. In addition to these methods, the disease progression scale based on both progression curves and a cubic regression model may be used to estimate saved time and its confidence interval. In this article, we compared the performance of these interval methods with regard to coverage probability and interval width under various scenarios to mimic the treatment effect in real trials. The backward projection method often has the coverage probability above the nominal level when the placebo disease progression curve is relatively smooth and the treatment effect size is large, at the cost of wider intervals. The intervals based on the disease progression scale have the coverage probability very close to the nominal level with a shorter interval width than other methods in many cases. Data from the phase 2 donanemab trial were used to illustrate the application of these interval methods.</p>