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The 7 quality tools – Ishikawa diagram

The Ishikawa diagram, also known as fishbone or cause and effect diagram, was first applied in 1953 in Japan by one of the greatest pioneers in quality control within organizations, Kaoru Ishikawa.

This tool aims to identify the root cause of a problem through a visual categorization of its potential causes. Its efficiency lies, among other factors, in allowing employees to avoid solutions that fix the problem peripherally and not thoroughly. It is important to emphasize that identifying proper and efficient solutions is a challenging task that we see many organizations struggle with.

The word fishbone comes precisely from its presentation format, made from a central unifying line that leads all potential causes, represented by the lateral spines, to a single effect. This scheme helps identify the main and secondary issues that contribute to the issue in question.

To use the Ishikawa diagram you must first choose a problem of any nature such as an audit, a claim from a customer, or a technical issue and place it at the right end of the spine, as indicated in the following image.


There are a few standard choices your organization can use for the lateral lines or “bones”. An example is the 6 M’s for manufacturing industries, that stand for Machines, Methods, Materials, Measurements, Mother Nature (Environment), and Manpower (People).

This is great to use in a company’s brainstorming session as it promotes discussion and analysis of all possible causes to a problem. When drafting the diagram, no cause should be disregarded and all options should be debated and considered. The facilitator can help the group rate each factor in accordance to their relevance and importance. This process can also help bring about issues that were not contemplated before.

With the cause or causes defined, the assertiveness in the identification of solutions is much greater. Establish an action plan with concrete and defined actions and hands-on!


QMS Certification Services is a fully accredited third-party International Certification Body. Operating since 1994, QMS is one of the oldest and most experienced certification bodies auditing and certifying thousands of organizations globally. We have built a great reputation for first-class service, market-leading pricing, and a hassle-free process for our clients. International Recognition: QMS Certification Services is accredited by IAS (INTERNATIONAL ACCREDITATION SERVICE) – a member of the IAF (International Accreditation Forum). All Certificates of Approval are issued under the IAS accredited system in the USA. QMS has auditors and clients all over the world, allowing for multi-country certification for clients.

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