Uncertainty estimation

What is uncertainty of measurement?

• Any measurement result is characterised by imperfections.
  
  
• There will always be an uncertainty about the value of a result: Result = Value ± Uncertainty.
  
  
• It is a quantitative indication of the quality of the result.
  
  
• It is the quantification of the doubt associated with a measurement result.
  
  
• It gives an answer to the question: How well does the result represent the value of the quantity being measured?
  
  
• There is an uncertainty even when correction factors have been applied, because there is an uncertainty on these factors.

The uncertainty of measurement is due to:

• Trueness: the closeness of agreement between the average value obtained from a large series of test results and the accepted reference value (true value).
  
  
• Precision: the closeness of agreement between independent test results obtained under stipulated conditions.