Measurement System Analysis

Process, Operation & Organizational Excellence

An experience where same item is measured repeatedly using different poeple or equipment is called Measurement System Analysis (MSA). MSA is used to quantify the amount of variation in a measure that comes from the measurement system itself rather than from product or process variation. MSA helps to determine the ways in which a measurement system can be improved.

Measurement System Analysis (MSA) assesses a measurement system for some or all of the below characteristics

Accuracy:

Accuracy is attained when the measured value has little deviation from the actual value

Repeatability:

Repeatability is attained when the same person taking multiple measurements on the same item or characteristic gets the same result every time.

Reproducibility:

Reproducibility is attained when other people (or other instruments or labs) get the same results you get when measuring the same item or characteristic.

Stability:

Stability is attained when measurements that are taken by one person in the same way vary little over time.

Adequate Resolution:

Adequate resolution means that your measurement instrument can give at least five (and preferably more) distinct values in the range you need to measure.

Traceability:

Traceability is an important concept in the trade of goods and services. Measurements that are traceable to the same or similar standards will agree more closely than those that are not traceable. This helps reduce the need for re-test, rejection of good product, and acceptance of bad product. Traceability is defined by the ISO International Vocabulary of Basic and General Terms in Metrology (VIM) as: “The property of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.”