This chapter covers scenario analysis using the Simio simulation software. Two systems are compared by undertaking a visual inspection of confidence interval graphs. For comparison across multiple systems, a multiple-scenario comparison is demonstrated, and the Simio OptQuest application is shown for optimisation. In chapter 9B, in order to undertake a confidence interval analysis of a single model, we made changes to the double-queue bank clerk model to make it a ‘true’ terminating system. Here, we will compare the performance of the double-queue system to the single-queue bank clerk system. To do this, load the double-queue terminating bank clerk simulation (see chapter 9B) into Simio. Make sure no new customers enter the bank after 480 minutes.