The International Standard gives guidance for ⎯ evaluation of measurement uncertainties using data obtained from studies conducted in accordance with ISO 5725-2:1994; ⎯ comparison of collaborative study results with measurement uncertainty (MU) obtained using formal principles of uncertainty propagation (see Clause 13). ISO 5725-3:1994 provides additional models for studies of intermediate precision. However, while the same general approach may be applied to the use of such extended models, uncertainty evaluation using these models is not incorporated in the present International Standard. This International Standard is applicable in all measurement and test fields where an uncertainty associated with a result has to be determined. This International Standard does not describe the application of repeatability data in the absence of reproducibility data. This International Standard assumes that recognized, non-negligible systematic effects are corrected, either by applying a numerical correction as part of the method of measurement, or by investigation and removal of the cause of the effect. The recommendations in this International Standard are primarily for guidance. It is recognized that while the recommendations presented do form a valid approach to the evaluation of uncertainty for many purposes, it is also possible to adopt other suitable approaches. In general, references to measurement results, methods and processes in this International Standard are normally understood to apply also to testing results, methods and processes.