Page 130 - The Six Sigma Project Planner

Chapter 3

Measure

Measurement Reliability and Validity

Before trusting the information, it is important to verify that it is reliable and valid.
For our purposes, we will say that information is reliable if we obtain essentially the
same information from more than one trusted source. For example, information on
employee morale might be available from an employee focus group, employee
interviews, and the annual employee survey.
We will say that information is valid if it covers the area of interest sufficiently well to
accurately represent the area of interest. For example, if the process serves a seasonal
market, the information should cover a complete business cycle, including the busy
season and the slow season.

Dimensional Measurement Analysis
To evaluate the reliability and validity of dimensional measurement systems, such as
gauges, conduct a gauge repeatability and reproducibility (R&R) study. Gauge R&R studies
are scientifically designed to quantify gauge error from a variety of sources.

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