Six Sigma Black Belt Certified Practice Exam

Which performance metric most effectively reflects process improvement in a Six Sigma project?

1. Return on investment (ROI)

2. Normalized data report

3. Customer satisfaction scores

4. Process capability indices

The correct answer is: Process capability indices

Process capability indices serve as a vital performance metric in a Six Sigma project because they quantitatively measure how well a process can produce outputs that meet specified requirements. These indices, often represented by terms like Cp, Cpk, Pp, and Ppk, indicate the capability of a process to produce products or services within given tolerances. When conducting a Six Sigma project, the primary goal is process improvement and achieving reduced variability. Process capability indices provide a direct indication of the improvements made. If these indices are increasing, it demonstrates that the process is becoming more capable of meeting customer specifications, which is a core objective of Six Sigma. Improvements in these indices reflect reductions in defects and variability, aligning perfectly with the overarching aim of improving process performance. While return on investment captures the financial benefits of improvements, it does not specifically measure process performance or capabilities. Normalized data reports can provide insights into data trends but lack the specificity regarding capability. Customer satisfaction scores, while important for understanding the outcomes from a customer perspective, are influenced by a multitude of factors beyond just the efficiency and capability of the process itself. In conclusion, process capability indices are essential for demonstrating tangible improvements in process performance as a result of Six Sigma initiatives, making them the most effective metric for reflecting