The application of control charts in breath alcohol measurement systems

Measurement provides numerical information, usually to assist in some decision process. Quality control is fundamental to the measurement process if the results are to provide confidence to the decision maker. The degree of quality control required depends on the context and purpose of the measurements. Quality control is particularly important in the forensic measurement of breath alcohol in light of the significant consequences involved. Control charts are an important and widely used tool in quality control for both measuring and manufacturing processes. They help evaluate measurement variability and provide a visual assessment of the system's state of statistical control. Control charts can be developed and applied in a variety of different ways. Several examples are illustrated that apply control charts to breath alcohol measuring systems. Application of these methods should result in improved process monitoring in addition to improved confidence for forensic purposes.