Ishikawa Fishbone Diagram; Cause and Effect; Continuous Process Improvement

The Fishbone diagram or Ishikawa diagram is an effective tool to help you visualize cause and effect and thus analyze data and help direct your team towards a solution to a problem. No business can survive long term unless it improves over time, this is best done as a planned program of continuous process improvement with data collection, data analysis then solution selection and implementation.

The Ishikawa Diagram or fishbone Diagram as it is often known due to its resemblance to said skeletal arrangement uses its structure to organize your data under specific related topics helping you to better understand how things are related and help you to identify cause and effect.

This and other quality tools will help you to drive continuous process improvement within your organization, improve your profits and grow your business.

The fishbone diagram was invented by Kaoru Ishikawa to try to organize problems solving teams thinking, hence the name Ishikawa diagram after its inventor. The name Fishbone diagram of course being derived from its resemblance to the skeleton of a fish. The Ishikawa or Fishbone diagram is a very effective tool for continuous process improvement.

The main aim of the use of the Ishikawa Diagram is to identify and organize the potential causes of an effect. For example you may have conducted your data collection on your factory floor and found that the biggest reason for rejects in your molding shop is “short shots” of material. This Effect then is placed at the head of your fishbone diagram as the effect that your looking for potential causes for. The “bones” coming from each direction on the spine of the fishbone are where you organize your potential causes.

The potential causes normally being generated through a brainstorming exercise either directly onto the diagram or as a separate exercise that is then organized within the Fishbone Diagram framework.

The bones coming from the main spine of the Ishikawa Diagram are usual named according to the 4, 5 or 6 Ms, depending on the complexity of the problem or the process that you are looking to improve.

The Four Ms are:

Manpower, the causes that can be attributed to the people working on the process, so things such as training would be placed on this arm of the diagram.

Methods, what is it about how we conduct the operation that can cause the effect that we are trying to solve such as machine setup process used.

Machines, the causes due to the machines or the equipment in the process, maybe you have more than one machine used for the process.

Materials, potential causes due to the materials used, such as the difference between two suppliers of the same material.

The 5^th and 6^th Ms are usually;

Mother Nature or the “M-vironment”, causes that are related to your surroundings such as external temperature or humidity.

Measurement or Metrics, Do we have causes that are more related to how we measure the process?

A brainstorming session to generate potential causes can come up with many potential causes of the effect in question. The team has to then analyze the potential causes to decide where to focus their attention.

The first stage is to highlight those that causes that are likely to be the main contributing factors, an easy way to do this is rate each cause, depending on how detailed you want to be this can be as simple as hot, warm or cold or rating from 1 to 10. Myself I prefer just to use hot, warm or cold, you can spend too much time arguing over whether it is a 3 or a 4 rather than getting on with resolving the issues.

The next stage is to look at the remaining “hot” causes and define actions to resolve them; these actions can then be rated against both their ease of implementation and the expense of implementation. The team first implementing those actions that are both easy and inexpensive!

The fishbone diagram and the data can be revisited on a regular basis as time passes to see how actions taken affect the problem in question. Thus you can drive continuous process improvement.

Continuous process improvement has to be planned and managed. Without a continual process of business improvement you will run the risk of losing out to your competitors. If your business is to flourish then you should use tools such as the Fishbone diagram or Ishikawa Diagram to drive continuous process improvement, other tools you could use are;

PDCA, Plan, Do, Check, Act, is a technique to plan your continuous process improvement in a methodical manner, a piece meal approach will not be as effective as a planned program of improvement.

Use the 5 Whys to help you define the real root cause of a problem, by asking why against each cause that you add to your fishbone diagram you can drill down further to your root causes.

Tally Sheets can be used to collect and analyze data to confirm or otherwise what you have detailed within your ishikawa diagram.

Brainstorming is the technique that you will probably use to populate your cause and effect diagram, the many causes will be generated through this technique and placed on the branches of your fishbone diagram, an alternative would be to arrange them using Mind Mapping.

Histograms and Bar Charts, can be used to analyze any data gathered from your fishbone diagram in a graphical and highly visual manner.

Pareto Analysis can then be used to highlight the vital few causes that have the greatest effect on the problem you are trying to solve using your ishikawa diagram.

Process mapping and Value Stream mapping can be used to highlight where in your process problems are occurring and target them for continuous process improvement.

Statistical Process Control (SPC) Charts can be used to monitor the process output and parameters where you have identified specific areas of concern using your cause and effect diagrams.

The following links will help you with regard to understanding and implementing quality tools such as the Ishikawa or Fishbone diagram and continuous process improvement;

Chartered Quality Institute (CQI); The Chartered Quality Institute can be joined by businesses or individuals who will then have access to their advice and publications.

American Society for Quality (ASQ); The American society for quality much like the CQI can offer much in the way of support with regard to continuous process improvement and the use of quality tools such as the fishbone or Ishikawa diagram.

Lloyds Register Quality Assurance (LRQA); Lloyds Register Quality Assurance is a global organization that has its roots in the UK, founded to provide quality assurance of shipbuilding for their insurers they are now one of the foremost bodies with regard to quality training and ISO certification.

British Standards Institute; The British Standards Institute or BSI like Lloyds is a global player in the Quality industry and also offer training in the areas of continuous process improvement for ISO 9001 and the implementation of quality tools such as the Ishikawa diagram.

American Standards Organization; The American Standards Organization can offer help, support and training in much the same way as Lloyds and BSI can.

Quality Institute of America; The Quality Institute of America can provide similar services to the Chartered quality institute in the UK.

Quality Institute in Healthcare; The Quality Institute for Healthcare can offer training and advice regarding continuous process improvement and quality tools within the healthcare industry.

Institute for Manufacturing (IFM); The Institute for Manufacturing has a very diverse team who have on the whole come from an industrial background rather than an accademic one, they are well versed as to which tools can be used in what situations.

These links will help you with finding out about fishbone diagrams, Ishikawa diagrams and other quality tools for continuous Process improvement.