4. Our advice

4.1 Multiply methods to detect all causes

The main disadvantage of the "5 Whys" is that it does not uncover causes that are not detected. To ensure that all causes have been identified, the "5 Whys?" method can be combined with the 5 M's (Manpower – Resources – Method – Material – Environment).

So, for every "Why did this happen?" question, the following questions should be asked one after the other:

• Are there any workforce-related causes?

• Are there any causes concerning the resources available?

• Are there any causes related to the Method used?

• Are there any causes related to the materials used?

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