"A graphical method for evaluating
whether a process is or is not in a 'state of statistical control.' The
determinations are made through comparison of the values of some
statistical measure(s) for an ordered series of samples, or subgroups,
with control limits" [ASQ]. In healthcare laboratories, the
Levey-Jennings chart is commonly used to plot the result observed for a
stable control material versus time, usually the day or run number.
The term "control chart" was found in the following pages: