By Patrick Waddick
Step 3: Ensuring Repeatability, Reproducibility, Accuracy and Stability
The data being collected (and measured) will be repeatable if the same operator is able to reach essentially the same outcome multiple times on one particular item with the same equipment. The data will be reproducible if all the operators who are measuring the same items with the same equipment are reaching essentially the same outcomes. In addition, the degree to which the measurement system is accurate will generally be the difference between an observed average measurement and the associated known standard value. The degree to which the measurement system is stable is generally expressed by the variation resulting from the same operator measuring the same item, with the same equipment, over an extended period.
Improvement teams need to be cognizant of all the possible factors that would cause reductions in repeatability, reproducibility, accuracy and stability - over any length of time - that in turn may render unreliable data. It is good practice to test, perhaps on a small scale, how the data collection and measurements will proceed. It should become apparent upon simulation what the possible factors are, and what could be done to mitigate the effects of the factors or to eliminate the factors altogether.
Next Page > The Data Collection Process
Page 1 > Building A Sound Data Collection Plan
Page 2 > Define Goals And Objectives
Page 3 > Operational Definitions and Methodology
Page 6 > After The Data Collection Process
Page 7 > Sample Populated Data Collection Plan
