Having an effective model for the nature of data will inevitably identify two different paths to process improvement. One path seeks to operate a process up to its full potential while the other path seeks to operate to meet requirements. This article explains how these two paths differ and how they can be used together to successfully improve any process.

In the classroom, two plus two is always equal to exactly four. Yet, when a manufacturer tries to lay down a two micron film on a two micron substrate, the result is seldom equal to exactly four microns. About the best that we can hope for is that the result will be four microns thick on average. And this is the basic difference between numbers and data.

Numbers inhabit the mathematical plane—where 1 is always 1, and 2 is always 2—and there is no uncertainty. Here, it can truly be said that two numbers that are not the same are different.

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