Accuracy vs. Precision

Understanding Accuracy vs. Precision

The words ‘accuracy’ and ‘precision’ are often used synonymously; however, as scientific terms they have different criteria, both of which need to be met to ensure an optimal measurement.

Accuracy relates to the closeness of a value to its true value; quantified as the tolerance in a measurement, whereas precision relates to the reproducibility and repeatability of a measurement i.e. the closeness of a set of results. These concepts can be visualised in the images below;

High Accuracy, Low Precision

Low Accuracy, High Precision

A measurement can be accurate but not precise, and conversely, precise but not accurate. Only if a measurement is both accurate and precise can it be considered optimal.

At ASDEC, we seek the highest levels of both accuracy and precision to ensure the highest quality of results for our customers. Our PSV-500 3D scanning lasers can achieve a positioning accuracy of ±0.1mm and a repeatability of ±1.5mm. Our fixed system, here at the ASDEC lab, is mounted to a KUKA Quantec industrial robot, which has a repeatability of ±0.06mm.

As our vibration measurements at ASDEC are made with laser light there is no mass loading distorting the structure and reducing measurement accuracy.  Likewise our Laser Vibrometers have a noise floor better than 10 nm/s ensuring high precision measurements every time.

Couple all of this with our temperature controlled and seismically isolated lab, allows ASDEC to provide the highest quality of results for our customers.

Watch how Matt Anticole puts things more into perspective with his lesson on ‘What’s the difference between accuracy and precision?’

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