THE FIRST ARTICLE in this series, ?Statistical process
control part 1: a primer for using statistical
process control in health care process improvement?
1 (in this issue of the Journal), introduced
the basic concepts of statistical process control
(SPC) and its main tool, the control chart. While
this set of techniques was originally developed in
the manufacturing sector, there is growing realisation
in recent years that SPC (and also other
quality improvement techniques, such as Six
Sigma and lean thinking) can be successfully
applied to health care quality improvement.2 The
reason for this is that SPC is a potent and
powerful, yet simple tool for tracking, and detecting
any variation in, process performance over
time; which creates the opportunity for health
professionals to promptly respond to any
improvement or deterioration in the process.
Perhaps the most valuable feature of SPC techniques
however, is the ability to place a change in
the outcome of a process in close temporal proximity
to the redesign and improvement of the
process. This means SPC can reliably evaluate the
effectiveness of quality improvement initiatives
implemented at the front line of health service
delivery, despite the complexities of the hospital
system and the challenges this often poses for
health services research (for example, the inability
to use robust research designs).
The purpose of this companion article is to
therefore demonstrate the practical application of
SPC in a health care organisation. Specifically, the
technique of control charting was used to track
the impact of patient flow process improvement
interventions in a public hospital, in the hope
that this will exemplify to health care professionals
the value and simplicity in applying SPC as
part of their daily work.