
MSA is defined as an experimental and mathematical method for determining the amount of variation present in a measurement process.
The variation in the measurement process can directly contribute to our overall process variability. The MSA is used to validate the measurement system for use by evaluating the accuracy, precision, and stability of the system.
What is the Measurement System?
A measurement system has been defined as a system of related measurements that allows certain characteristics to be quantified. It may also include a set of indicators, fixtures, software, and personnel necessary to verify a particular unit of measure or make an assessment of the measured property. Sources of variation in a measurement process can include:
– Process – test method, specification
– Personnel – operators, skill levels, training, etc.
– Tools / Equipment – gauges, fixtures, test equipment used and their associated calibration systems
– Items to be measured – samples of the part or material being measured, sampling plan, etc.
– Environmental factors – temperature, humidity etc.
All these possible sources of variation should be considered during Measurement System Analysis. Evaluation of a measurement system should include the use of specific quality tools to identify the most likely source of variation. Most MSA activities examine two main sources of variation; parts and their measurement. The sum of these two values represents the total variation in a measurement system.