Training and consultancy for testing laboratories.

Archive for January, 2019

How to determine significant systematic error?


When over time, you carry out several batches of analysis on a certified reference material (CRM) and find that the mean values are apparently to be consistently different from the expected value given in the certificate of analysis of the CRM sample, your analytical method may have a systematic error. Such error affects the method trueness and accuracy.

Determining significant systematic error

Examples on how to calculate combined standard uncertainty (edited)

Uncertainty calculation

It is very important for anyone interested in the evaluation of measurement uncertainty to fully understand the very basic principles in calculating the combined standard uncertainty.  Let’s look at some worked examples ….