Increasing requirements to conform to international standards for quality assurance, such as ISO 17025, are driving a need for appropriate methods for the estimation of measurement uncertainty throughout the chemical industry. This volume provides specific insights on measurement uncertainty causal factors and how they are addressed for chemical measurement systems. It includes practical examples that illustrate uncertainty estimation in a manner compliant with the Guide to the Expression of Uncertainty in Measurement (GUM). Chapters on the uncertainty of sampling and interpreting uncertainties in a compliance situation are included.