ABSTRACT
No measurements are correct. To get a value of the measurement error, people need to perform a calibration. This chapter presents an introduction to uncertainty calculation – a standardised way to estimate how good a measured value is. Basically, the uncertainty can be handled in three different ways. Either it is the 'supplier' or the 'customer' who takes the risk or else, the risk or uncertainty is shared between both of them. Compared to conformity assessment, uncertainty has similar effects in process control; however, large uncertainties may result in the need for larger 'production safety margins'. The uncertainty consists of two parts: one systematic and one random. The total uncertainty of a measurement system can be estimated by doing an uncertainty budget. An uncertainty budget can also assist to find best actions for improvements. This calculation indicates that the two largest contributions are the initial error (the specified accuracy) and the long-term stability (drift).
