Avoid Two Common Mistakes in Measurement System Analysis

Measurement system analysis (MSA) determines whether the measurement system is adequate and confirms that significant error is not introduced to the true value of a process characteristic. MSA is the one of the most misunderstood and underused concepts in Six Sigma. This article highlights two of the common mistakes made during the study and explains…


Use Earned Value Management for Process Improvement

Whenever there is an issue in a process, attempts are made to identify the process step that is causing the problem, identify the root cause and come up with a corrective or preventive action. The time taken to identify the “right” process step is directly proportional to the number of process steps involved and it…


A Simple Model of a Variance Stable Process

Most fairly accurate descriptions of equipment and/or process lifetimes assume that failure rates follow a three period I II III “bathtub-curve pattern” where failures/errors: I – Decrease during the debugging or improvement time period. II – Remain relatively constant and at their lowest levels during the normal equipment or process operating period. III – Increase…


What You May Not Know About Adding Variances

Imagine for a moment that your Six Sigma project does not have the rigorous measurement system you would like it to have, and you have to calculate your primary metric from a few inputs instead of measuring it directly. Or perhaps you are designing a new product and want to understand how the variability in…