Building an Even Better Standard
Those of you involved in test method development know that the ASTM International requirement for precision and bias statements represents no small amount of work on the part of your committee. A full precision and bias statement shows potential users that the method itself has been tested and proved valid and, taken together, these statements add to the attributes that make ASTM test methods so well-respected around the world.
A solid P&B statement is often arrived at after a committee has overseen interlaboratory studies, which take time and often a great deal of coordination by the group’s volunteer members. Recognizing both the value of the P&B statement to its test methods — and the valuable time of its members — ASTM International launched the Interlaboratory Study Program five years ago. The program, administered by ASTM staff, lends a helping hand to committees for any and all aspects of conducting interlaboratory studies, from finding labs to participate, to helping coordinate sample shipment, to the preparation of statistics and P&B statements.
In this issue, we look at the ILS Program through the lens of one significant interlaboratory study undertaken by Committee E56 on Nanotechnology. With the publication of E2490, Guide for Measurement of Particle Size Distribution of Nanomaterials in Suspension by Photon Correlation Spectroscopy, the committee undertook to develop its precision and bias statement with the help of the ASTM ILS Program. The study utilized results from 26 laboratories, but that was not the only collaboration for this particular work. Gold nanoparticle reference materials that had been developed by the National Institute for Standards and Technology, with partial funding from the National Cancer Institute, were used in the testing. Along with NIST, NCI’s Nanotechnology Characterization Laboratory was heavily involved in the development of the study program. The result is a nanotechnology measurement tool — supported by precision and bias statements validated by rigorous testing — that is a major contribution to international nanotechnology standardization.
Standards developing organizations, by their nature, excel at bringing stakeholders together. By helping technical committees gather the necessary resources to create valid P&B statements, the Interlaboratory Study Program is one more element in ASTM’s toolbox for building an even better standard.