In process improvement, which concept is primarily focused on understanding customer requirements?

The correct choice focuses on Critical to Quality (CTQ) aspects, which are essential in process improvement to ensure that the customer's needs and requirements are understood and met. CTQ is a key concept used to identify the specific attributes that are critical for customers, translating their needs into measurable requirements that can guide process improvements.

By identifying CTQs, organizations can align their processes with customer expectations, ensuring product quality and service reliability. This focus enables teams to prioritize enhancements that will have the most significant impact on customer satisfaction and ultimately the success of the organization.

In contrast, while ROI (Return on Investment) refers to measuring the financial benefits of a project compared to its costs, it does not directly pertain to understanding customer requirements. Six Sigma is a methodology focused on reducing variation and defects within processes, which indirectly supports customer satisfaction but focuses more on statistical quality control rather than directly identifying customer needs. Lean aims to eliminate waste and optimize flow in processes, which enhances efficiency but does not specifically target customer requirements like CTQ does.