BS ISO 5725-4:2020

What is ISO 5725‑4 about?  

ISO 5725 is a series of international standards on measurements that discusses the procedures and specifications to keep a check on the bias of different methods. ISO 5725‑4 is the fourth part of the ISO 5725 multi-series. ISO 5725‑4 specifies basic methods for estimating the bias of a measurement method and the laboratory bias when a measurement method is applied, provides a practical approach of a basic method for routine use in estimating the bias of measurement methods and laboratory bias, brief guidance to all personnel concerned with designing, performing or analysing the results of the measurements for estimating bias. 

ISO 5725‑4 applies when the measurement method has been standardized and all measurements are carried out according to that measurement method. 

ISO 5725‑4 applies only if an accepted reference value can be established to substitute the true value by using the value, for example: 

• Of a suitable reference material; 
• Of a suitable measurement standard; 
• Referring to a suitable measurement method; 
• Of a suitable prepared known sample. 

ISO 5725‑4 applies only to the cases where it is sufficient to estimate bias on one property at a time. 

NOTE: ISO 5725‑4  is not applicable if the bias in the measurement of one property is affected by the level of any other property (i.e. it does not consider interferences by any influencing quantity). Comparison of the trueness of two-measurement methods is considered in ISO 5725-6. 

Who is ISO 5725‑4 for?  

ISO 5725‑4 on the accuracy of measurement methods and results is beneficial for: 

• Metrologist 
• Laboratory quality assurance  

Why should you use ISO 5725‑4? 

A measurement process is biased if it systematically overstates or understates the true value of the measurement. 

ISO 5725‑4 provides guidance regarding the determination of the bias of a standard measurement method by an interlaboratory experiment, determination of the laboratory bias of one laboratory using a standard measurement method 

ISO 5725‑4 helps the user to determine measurement bias and laboratory bias and assist him to minimize the error. ISO 5725‑4 helps you analyze and test various measurement and measuring methods. In this manner, you can achieve precision in the measurement process and establish accurate results. 

What’s changed since the last update?  

BS ISO 5725‑4:2020 supersedes BS ISO 5725‑4:1994, which is withdrawn. 

The main changes compared to the previous edition are as follows: 

• Clearly recognizing the requirements of the accepted reference values used in bias evaluation experiments and introducing the uncertainties of the accepted reference values 
• Changing examples with a currently used measurement method