For the ease of understanding, this author is using the word ‘piece’ to mean (in the generic sense) the making of a tangible product. It could be an ice cream cone, a widget, or an automobile. One of the tenets of lean is single piece flow. Instead of building up a stack of inventory between the steps in the process, the idea with single piece flow (also known as one piece flow), is to build at the pulse rate of customer demand. This pulse rate of customer demand, known as takt time, ebbs and flows over time. With single piece flow, the idea is to make a piece only when the customer asks for one.

The mapping process starts with identifying the customers’ needs and requirements. The team then determines the outputs of the process that have an effect on those requirements. The team lists 5 to 7 high-level steps of the process. They begin to identify the inputs to the process and the suppliers who provide for those inputs. SIPOC is an effective way of seeing the whole value-add process on one graphic. It shows the relationships between inputs and outputs.

There may be thousands of factors that directly affect or interact with each other to affect the outcome of some desired result(s) of a process. The 6M’s started with Dr. Ishikawa as the 4M’s (Machine, Material, Method, Measurement) and over time it evolved to including the human element and noise factors affected by the forces of nature (e.g., humidity, vibration, temperature, etc.) The team uses these 6M’s as memory joggers to focus on when they are identifying as many of the factors that might influence the process as possible. Typically, they will use a Fishbone Diagram along with brainstorming to gather these ideas. After the team has exhausted the brainstorming session, the team will then boil down the many factors to the vital few factors from which they will place their monitoring, controlling, and improvement methodologies.

Six sigma is a process improvement methodology which at its core focuses on making virtually any process more effective and efficient.

A spaghetti diagram (also known as a workflow analysis diagram) is used to present the workflow or movement of people, materials, and information through a process.
A spaghetti diagram is particularly useful in identifying inefficiency and waste in a process.

Stem-and-leaf plots (also known as stem-and-leaf diagrams) are a valuable combination of a check sheet and a histogram in which the actual data values are recorded so that the raw data is maintained and the distribution of the data is also obvious for all to see. The data are divided into leading digits (‘stems’) and trailing digits (‘leaves’).

The steering committee is an upper management level team whose job it is to craft the strategic approach to process improvement.

Statistical Process Control (SPC) is a process improvement methodology to monitor, control, and continuously optimize a process. SPC is really a subset of six sigma. SPC is usually associated with control charts and design of experiments.

SPC separates common-cause from assignable-cause variation. The team identifies and removes assignable-cause variation and reduces common-cause variation around three targets – – nominal-is-best, larger-is-better, or smaller-is-better characteristics.

A mathematical method that employs probability theory for inferring the properties of a population parameter from which the sample is taken is known as inferential statistics. Inferential statistics is a set of methods used to make generalizations, estimations, or predictions. Example: If determining the statistical capability of a process, we would take periodic samples of parts from a process and from these samples we would make inferences about the performance of the whole population of parts produced by the process.

Standard work is simply the best way to do a particular task or a process. ‘best’ means consistent, meeting customer requirements, efficiency, and safety. Standard work is a philosophy of continuous, on-going improvements and it should be included in all work areas.