This chapter describes the third stage, analyze. It is at this stage that we begin to look at the collected data to identify the root causes that contribute certain effects to the final outcome of the process. The objective is to identify and prioritize all the possible causes of variation so that actions can be taken to improve the process. This chapter will describe the core objectives of the analyze stage along with the tools and techniques to achieve these objectives. At the end of the chapter, we will see the application of this stage to our case study.