Basic terminology and Figures

Pareto

Download Products

The Pareto principle states that 80% of the impact of the problem will show up in 20% of the causes. (Originally stated: 80% of the wealth is owned by 20% of the people.)A bar chart that displays by frequency, in descending order, the most important defects. Proper use of this chart will have the cumulative percentage on a second y-axis (to the right of the chart). This chart-type is used to identify if the Pareto principle is evident in the data. If the Pareto principle is evident, about 20% of the categories on the far left will have about 80% of the impact on the problem.

Cause & Effect Diagram

The cause & effect diagram is the brainchild of Kaoru Ishikawa, who pioneered quality management processes in the Kawasaki shipyards, and in the process became one of the founding fathers of modern management. The cause and effect diagram is used to explore all the potential or real causes (or inputs) that result in a single effect (or output). Causes are arranged according to their level of importance or detail, resulting in a depiction of relationships and hierarchy of events. This can help you search for root causes, identify areas where there may be problems, and compare the relative importance of different causes.

Causes in a cause & effect diagram are frequently arranged into four major categories. While these categories can be anything, you will often see:

  • manpower, methods, materials, and machinery (recommended for manufacturing)
  • equipment, policies, procedures, and people (recommended for administration and service).

These guidelines can be helpful but should not be used if they limit the diagram or are inappropriate. The categories you use should suit your needs. At SkyMark, we often create the branches of the cause and effect tree from the titles of the affinity sets in a preceding affinity diagram.

The C&E diagram is also known as the fishbone diagram because it was drawn to resemble the skeleton of a fish, with the main causal categories drawn as "bones" attached to the spine of the fish, as shown below.

Cause & effect diagrams can also be drawn as tree diagrams, resembling a tree turned on its side. From a single outcome or trunk, branches extend that represent major categories of inputs or causes that create that single outcome. These large branches then lead to smaller and smaller branches of causes all the way down to twigs at the ends. The tree structure has an advantage over the fishbone-style diagram. As a fishbone diagram becomes more and more complex, it becomes difficult to find and compare items that are the same distance from the effect because they are dispersed over the diagram. With the tree structure, all items on the same causal level are aligned vertically.

To successfully build a cause and effect diagram:

  1. Be sure everyone agrees on the effect or problem statement before beginning.
  2. Be succinct.
  3. For each node, think what could be its causes. Add them to the tree.
  4. Pursue each line of causality back to its root cause.
  5. Consider grafting relatively empty branches onto others.
  6. Consider splitting up overcrowded branches.
  7. Consider which root causes are most likely to merit further investigation.

Other uses for the Cause and Effect tool include the organization diagramming, parts hierarchies, project planning, tree diagrams, and the 5 Why's.

Flowchart

A flowchart is a graphical representation of a process, depicting inputs, outputs and units of activity. It represents the entire process at a high or detailed (depending on your use) level of observation, allowing analysis and optimization of workflow.A flowchart is a graphical representation of a process. It represents the entire process from start to finish, showing inputs, pathways and circuits, action or decision points, and ultimately, completion. It can serve as an instruction manual or a tool for facilitating detailed analysis and optimization of workflow and service delivery.

Cause and Effect Diagram

A cause and effect diagram is a visual tool used to logically organize possible causes for a specific problem or effect by graphically displaying them in increasing detail. It helps to identify root causes and ensures common understanding of the causes. It is also called an Ishikawa diagram.Cause and Effect relationships govern everything that happens and as such are the path to effective problem solving. By knowing the causes, we can find some that are within our control and then change or modify them to meet our goals and objectives. By understanding the nature of the cause and effect principle, we can build a diagram to help us solve everyday problems every time.

Cause and Effects Matrix

Relates the key inputs to the key outputs (customer requirements) using the process map as the primary information source

Key outputs are scored as to importance to the customer

Key inputs are scored as to relationship to key outputs

Pareto of key inputs to evaluate in the FMEA and control plans

Input into the initial evaluation of the Process Control Plan

Cause & Effect Matrix Steps

Identify key customer requirements (outputs) from process map or other sources

Rank order and assign priority factor to each Output (usually on a 1 to 10 scale)

Identify all process steps and materials (inputs) from the Process Map

Evaluate correlation of each input to each output

  • low score: changes in the input variable (amount, quality, etc.) have small effect on output variable
  • high score: changes in the input variable can greatly affect the output variable

Cross multiply correlation values with priority

Cause & Effect Matrix Form

Rating of Importance to Customer
1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12 / 13 / 14 / 15
Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Requirement / Total
Process Step / Process Input
1 / 0
2 / 0
3 / 0
4 / 0
5 / 0
6 / 0
7 / 0
8 / 0

Process Map

It is a hierarchical method for displaying processes that illustrates how a product or transaction is processed. It is a visual representation of the work-flow either within a process - or an image of the whole operation. Process Mapping comprises a stream of activities that transforms a well defined input or set of inputs into a pre-defined set of outputs.
The High Level Process Map; "30,000 feet overviews", "Medium image" is differentiated from the Detailed Process Map; "homing in", "zooming in", "Micro Map". The High Level Process Map is utilized in scoping a Six Sigma project and establishing boundaries, while a detailed process map will be used by the GB/BB to Analyze (identify potential causes) and Improve (optimize) the process.
A good Process Map should:
1)allow people unfamiliar with the process to understand the interaction of causes during the work-flow.
2)contain additional information relating to the Six Sigma project i.e. information per critical step about input and output variables, time, cost, DPU value.
Software programs utilized to create Process Maps include Microsoft Visio, SigmaFlow and iGrafx. For those individuals who may not have access to these packages, Process Mapping may be performed in Excel or Power Point.

Value Stream

A value stream is all the steps (both value added and non-value added) in a process that the customer is willing to pay for in order to bring a product or service through the main flows essential to producing that product or service.

Value Stream Mapping

Value stream mapping is a paper and pencil tool that helps you to see and understand the flow of material and information as a product or service makes its way through the value stream. Value stream mapping is typically used in Lean, it differs from the process mapping of Six Sigma in four ways:
1) It gathers and displays a far broader range of information than a typical process map.
2) It tends to be at a higher level (5-10 boxes) than many process maps.
3) It tends to be used at a broader level, i.e. from receiving of raw material to delivery of finished goods.
4) It tends to be used to identify where to focus future projects, subprojects, and/or kaizen events.
------
A value stream map (AKA end-to-end system map) takes into account not only the activity of the product, but the management and information systems that support the basic process. This is especially helpful when working to reduce cycle time, because you gain insight into the decision making flow in addition to the process flow. It is actually a Lean tool.
The basic idea is to first map your process, then above it map the information flow that enables the process to occur.

Lean Manufacturing

Download Products
Lean Six Sigma Champion Training
Six Sigma Leadership Series
Lean Six Sigma Team Member Training Course

Initiative focused on eliminating all waste in manufacturing processes.
The Production System Design Laboratory (PSD), Massachusetts Institute of Technology (MIT) states that 'Lean production is aimed at the elimination of waste in every area of production including customer relations, product design, supplier networks and factory management. Its goal is to incorporate less human effort, less inventory, less time to develop products, and less space to become highly responsive to customer demand while producing top quality products in the most efficient and economical manner possible.'
Principles of Lean Enterprise:

 Zero waiting time

 Zero Inventory

 Scheduling -- internal customer pull instead of push system

 Batch to Flow -- cut batch sizes

 Line Balancing

 Cut actual process times.