Uncertainty is important when carrying out critical, absolute measurements and is not important when making relative measurements.

For example, when measuring breaking forces for seat belts, it might be important to know if it breaks at 740 lbs or 760 lbs. If, however, measurements are being made on the force required to press fit gearbox bearings on an automotive production line, the absolute value of the load may not be as important as to ensure that the same load is applied every time.

Uncertainty is very important when calibrating load cells. Calibration is the time that a load cell is checked on how it measures absolute loads and also is checked against the National Standards or loads that are traceable to the National Standards.