Pulmonary artery pressures and arterial pressures are important hemodynamic measurements utilized in clinical management decision making for critically ill patients. Studies have demonstrated a concerning rate of measurement error, often due to technical errors. Zeroing, leveling, and dynamic response testing are essential components of assuring the quality of measurements. This article describes a multilevel approach to assuring the accuracy of measurements. It includes the physics underlying each of these principles, criteria for judging the efficacy of the dynamic response, and clinically applicable methods for measuring the natural frequency and damping coefficient of pressure monitoring systems.