AATCC M10-2018, A Summary of ASTM Methods for Interlaboratory Testing, brings together the ASTM practices that apply when two or more laboratories compare results on the same material. It summarizes the statistical treatment of interlaboratory data, the preparation of test samples and the reporting of precision statements. The summary is a reference for laboratory managers, quality systems staff and technical committees that need to demonstrate the comparability of test results between sites.