In Six Sigma, CTQs (short for Critical-to-Quality) are understood as critical quality attributes necessary to achieve high-quality processes, products, or services that meet customer needs. CTQs are measurable characteristics that ensure customer satisfaction. To identify them, an analysis of the Voice of Customer (VoC) is required. This analysis helps identify customer requirements that are not inherently measurable, which are then translated into CTQs. EA useful tool for making these requirements measurable and specific is the CTQ tree, which represents customer desires as a tree diagram, allowing for a more precise categorization.