This book presents a set of process improvement principles that can be applied by managers to improve the design and operation of their production systems encompassing both manufacturing and service systems.

A production system is comprised of one or more resources that are utilized to perform useful work. In a manufacturing setting the resources might include machines, tools, operators, and material handling devices. In a service system such as a health clinic the resources might include a waiting area, doctors and nurses, imaging equipment, and exam rooms. In either case the availability of resources limits the flow of work through the system.

An entity is the work item that moves through the system. Note that an entity might be a part that we are manufacturing, a patient that we are treating in an emergency department, a passenger that we are processing at an airport, or a business transaction that we are executing. The process improvement principles that we develop will apply equally to all these different types of systems.

Our objective is to design and run production systems that can efficiently process entities using the resources that we have allocated to the system. We want our entities to be processed with least cost and in a timely manner.

We will use simulation models as the primary method for establishing our process improvement principles. We use simulation because of its ability to capture variability within our processes as well as its flexibility to quickly and easily model a wide range of production systems. A simulation model is able to "act out" the movement of entities through the system, and capture the impact of limited resources on the system performance. We can also watch animations of our systems, and gain insights into the system behavior. We can quickly evaluate many different system alternatives, and compare key performance indicators (KPI's) to select the best strategies. Although we will make use of many different simulation models in our analysis, there is no need for the reader to be skilled in building their own simulation models as they are provided and can be run with freely downloadable software.

This book does not propose or present a process improvement methodology such as Six Sigma or Lean. Instead it presents and illustrates basic principles for process improvement that can be used with any methodology within your process improvement projects. For example within a Six Sigma project methodology involving the five phases of Define, Measure, Analyze, Improve, and Control, this book is focused on the fourth phase by presenting principles that improve process performance.

This book is targeted at busy managers and therefore is intentionally short in length. The goal of this book is to concisely convey the process improvement principles in as few words as possible.