Ideally, interlaboratory testing of a method is carried out by a randomly chosen group of laboratories that typifies the kind of laboratory that is likely to use the method. In actuality, this ideal is only approximated by the laboratories that are available and willing to undertake the test work. The coordinator of the program must ensure that every participating laboratory has appropriate facilities and personnel and performs the method exactly as written. If this goal is achieved, the statistics developed during the ILS will be adequate for determining if the method is capable of producing satisfactory precision in actual use. If the program includes certified reference materials, the test data also provide information concerning the accuracy of the method. The statistics provide a general guide to the expected performance of the method in the laboratories of those who will use it.

1.1 This practice presents procedures and statistics for an interlaboratory study (ILS) of the performance of an analytical method. The study provides statistical values which are useful in determining if a method is satisfactory for the purposes for which it was developed. These statistical values may be incorporated in the method's precision and bias section. This practice discusses the meaning of the statistics and what users of analytical methods may learn from them.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.