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The most well-known problem solving tool, 5M is a simple and efficient tool for exhaustively enumerating the probable causes of an issue.


The 5M, also known as a fish-bones diagram, cause/effect diagram or Ishikawa diagram, is a basic tool for piloting problem-solving projects. Created by Kaoru Ishikawa in the post-war period, this tool has the advantage of being visual and helping the project pilot to share and communicate around the problem solving project.

This Japanese chemical engineer was one of the forerunners of quality management and quality circles, developed the following ideas:

  • Ubiquity of quality at every process
  • Involvement of all the company’s actors in quality
It is noted that the idea of cause-to-effect relationships is not new. The first traces of this philosophy come from Buddha. Buddhism is based on the law of cause and effect. According to Buddha, this law consists of essential directives:

  • Good deeds are good results.
  • Bad deeds give bad results.
  • Your own actions bring your own results.
  • Each effect has a cause and condition that combine.
  • An effect has at least two causes: “As a net is made up of a series of nodes, everything in the world is connected by a series of nodes”.

The idea developed here by Buddha is therefore contrary to 2 tools of the problem resolutions widely widespread:

  • The 5 why indicating that the cause-effect relationship is a linear relationship: cause-effect, cause-effect.
  • The 5M which consists in creating categories of causes (methods, material…)

The principle

This diagram summarizes the various possible causes of a problem graphically. It classifies these causes according to 5 large families:

  • material : The various consumables used, raw materials, take the point on handling and packaging…
  • Management : The place of work, its appearance, its physical organization (5S), the parameters of the environment (temperature…) If these can have an influence on the product/process…
  • Methods : The procedures of manufacturing, handling, control, flow of information…
  • Machine : equipment, machinery, tools, spare parts
  • Man Human resources, staff qualifications


A visual and synthetic tool, it is used by the facilitator of the improvement project to better communicate and brainstorm with the team. The process is as follows1 :

  1. Ask the problem by starting with ” why ?  »
  2. To bring out all ideas, all possible causes
  3. Then classify the ideas in one of the five families
  4. Identify, by vote eventually, the most probable causes
  5. Once the tests are carried out and the actual cause is identified, we can apply the 5 Why to go back to the root cause

From 5M to 10m, passing through 4m

Many variants of the 5M exist. From 6m, at 8m, in some cases we have passed to 10m or to 4m. It depends on your sector of activity (industry, services…), your particular constraints (market change…). Some are the number of M, the stakes always remain the same: to be able to classify and identify all the possible causes of a problem.

The 4m analysis is generally used as part of the TPM. Focusing on equipment, the 4m analysis aims to look for causes on all families except on the middle family.

Here is an example of 8m suitable for industry2 :

  • 6m – Measurement : Indicators-related errors used to quantify the phenomenon to be analyzed.
  • 7m -Management and financial means: Organizational problem or simply budget.
  • 8m – Maintenance : problem related to the maintenance of the production tool generating fault and other problems.

An example of 10msuitable for services :

  • 9m – Market : Difficulty in ” reading ” The market which can vary a lot and generate problems in the company
  • 10m – Threat : Technology change, increased competition… can be risks that cause different problems.


1 – F. Gillet-Goinard, B. Seno – The tool box of the quality manager

2-P. Schiesser (2012) – Practice of eco-design in 53 tools

3-F. A. Meyer (2012) – The OCD Revolution Lean Six Sigma in Services

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