Once quality indicators are identified, the best means of monitoring them must be determined. The use of statistical methods to monitor and control a process, known as Statistical Process Control (SPC), seems particularly promising for monitoring quality indicators. SPC uses rigorous time-series analysis methods, whose results are reported as a graph of changes in outcome rates over time. Moreover, SPC can help to determine whether these changes are real (i.e., related to a causative factor) or merely a manifestation of natural variability. Among SPC tools, CUmulative SUM (CUSUM) charts are widely used for industrial quality control and have been found effective for measuring and monitoring healthcare outcomes.