2. Measurement Process Characterization
2.1. Characterization
2.1.1. What are the issues for characterization?

2.1.1.1.

Purpose

Purpose is to understand and quantify the effect of error on reported values

The purpose of characterization is to develop an understanding of the sources of error in the measurement process and how they affect specific measurement results. This section provides the background for:

• identifying sources of error in the measurement process
• understanding and quantifying errors in the measurement process
• codifying the effects of these errors on a specific reported value in a statement of uncertainty

Important concepts

Characterization relies upon the understanding of certain underlying concepts of measurement systems; namely,

• reference base (authority) for the measurement
• bias
• variability
• check standard

Reported value is a generic term that identifies the result that is transmitted to the customer

The reported value is the measurement result for a particular test item. It can be:

• a single measurement
• an average of several measurements
• a least-squares prediction from a model
• a combination of several measurement results that are related by a physical model