Purpose: This Engineer Manual (EM) provides specific guidance, procedures, criteria, and tools for implementation of the U. S. Army Corps of Engineers (USACE) Performance Evaluation (PE) Program. Performance evaluation of analytical chemistry laboratories is recommended to ensure that technically competent and reliable laboratories are employed to generate analytical data of acceptable quality. This EM is intended for use by USACE personnel as a critical companion document to ER 1110-l-263.