This document provides guidance on validating analytical procedures according to the International Conference on Harmonization. It defines key terms and outlines the validation characteristics that should be evaluated for identification tests, assays for active ingredients or impurities. These include accuracy, precision, repeatability, specificity, detection limit, quantitation limit, linearity, range, and robustness. The document provides detailed methodology for testing each validation characteristic on analytical procedures to demonstrate the procedure is suitable for its intended use.