Analysis of Variance (ANOVA)

Analysis of variance, also known as ANOVA, is a sophisticated statistical modeling technique that looks at variation within and between two or more groups.

This is a useful tool in Six Sigma because being able to recognize variation in results lets you zero in on the process that created that variation. The statistics behind the tool also help you isolate the general fluctuation (randomness) of a process from special cause variation. Sometimes differences in output are subtle, so this sort of tool lets the analyst apply rigor to the observation and ensure that the variation is actually statistically significant.

Note that using analysis of variance (ANOVA) is not something that the typical employee can do. It takes special expertise, and can require considerable time in data collection.

For that reason, it is not commonly used in daily improvement efforts. That said, it does have its place when there is a particularly challenging problem that has been attacked with less sophisticated tools.