In reality it is often a combination of the two, for example if a sample is analysed, or one (or more) of its properties is measured by different laboratories using different methods, or even just by different units of equipment of identical construction.
A round-robin program is a measurement systems analysis technique which uses analysis of variance (ANOVA) random effects model to assess a measurement system.
Companies are obliged to determine whether hazardous substances are in the air at the workplace by using appropriate measurements.
The Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) provides proficiency testing as support and assistance for the measuring stations worldwide for the purpose of self-examination and for the external presentation of quality standards.
The IFA organises the proficiency testing schemes in co-operation with the German association of environmental and OSH measurement bodies (BUA) and in collaboration with international partner institutes.