4.1 Proficiency testing is a means of securing estimates of the variability of results obtained by different laboratories testing homogeneous materials taken from batch samples when following procedures prescribed in a specific test method.

4.1.1 For the purpose of this guide, homogeneous materials are considered to be laboratory samples cut from the same batch sample (roll or garment lot) and selected at random for the participant laboratories.

4.2 This proficiency test program is to be considered a full-scale interlaboratory test, in which a reasonably large number of laboratories participate by testing a series of materials using one or more operators per laboratory and report the data for analysis.

4.2.1 For the purposes of this guide, Full Scale Laboratory Test is defined in Practice D2904. This is not to be confused with the full scale testing terminology and definitions which appear in other test methods, such as flammability, that describe the size of the specimens being tested.

4.3 The statistical data generated by this practice provide information needed to exhibit participation in a formal proficiency test study.

4.4 All data are submitted to the program coordinator at ASTM Headquarters for the preparation and distribution of the proficiency testing program reports. All laboratory data are confidential with no disclosure of lab identity except for each participant's own laboratory. Published reports contain all laboratory test data (coded), statistical analysis of test data, charts plotting test results versus lab code, and other information.