ASTM E691-20 PDF Download

An interlaboratory study (ILS) of a test technique can be planned, carried out, and analyzed, and its findings can be interpreted according to the ASTM E691-20 standard. This exercise's goal is to collect data that will be used to help create a test method's precision statement.

The standard highlights that ASTM regulations call for precision claims in test methods, which are crucial for a number of reasons, including comparing test results to reference values or between data sources. The degree of agreement between test results received from various sections of a substance is used to gauge how precise a test procedure is. The accuracy is determined by the variability of the test results, with higher variability suggesting lower precision.

Statistics such as the standard deviation, coefficient of variation, variance, or a precision limit are used to report the precision. The standard also states that data from interlaboratory research can be utilized to determine the bias of the test procedure if recognized reference values are available.

Planning, testing, and data analysis are the three fundamental processes of an interlaboratory study that are outlined in the standard. The interlaboratory study task group must be established, the study must be designed, participating laboratories must be chosen, test materials must be selected, and the protocol must be written. Getting ready and distributing the supplies, working with the collaborating labs, and managing the test result data are all part of the testing phase. During the data analysis stage, a variety of methods are used to assess the consistency of the data, spot out-of-the-ordinary values, and compute numerical measures of precision, particularly repeatability and reproducibility.