Certified Quality Engineer (CQE) Practice Exam 2026 - Free Quality Engineer Practice Questions and Study Guide

Process capability is a critical concept in quality engineering that evaluates how well a process can produce output within specified limits. Measuring process capability involves assessing statistical indices that indicate how much variation exists in a process relative to the allowable limits.

Using capability indices like Cp (process capability index) and Cpk (process capability performance index) provides quantitative measures of how a process performs relative to its specifications. The Cp index measures the potential capability of a process by comparing the width of the specification limits to the width of the process variability. In contrast, Cpk takes into account the mean of the process and its deviation from the target value, thus providing insight into how centered the process is within the specification limits.

This statistical approach allows quality engineers to determine if a process is capable of meeting quality standards consistently, which is essential for quality control and improvement initiatives. By focusing on these capability indices, engineers can make informed decisions about process adjustments, improvements, and capability enhancement efforts.

In contrast, measuring the number of products produced does not provide insight into the quality or consistency of those products. Customer satisfaction surveys, while valuable for understanding customer perceptions, do not quantify process capability in terms of statistical performance. Comparing processes with competitors may offer some benchmarking context but does not establish internal capability metrics directly