Root Cause Analysis

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for Root Cause Analysis

5 WHY

e 5 Why method is used to dig deeper until the true root cause of an

occurrence is identied. e root cause can be pursued by asking why

continuously, or the process can be split when an occurrence could have

multiple causes (Ohno, 1988). e whys can be, but do not need to be,

placed in boxes like a owchart/ fault tree. e 5 Why method should lead

from the proximate cause to the ultimate cause.

Key Points

• Asking why ve times can lead to the true root cause of an occurrence.

• is method should be used in support of other, more quantita-

tive, methods.

• It can be used for occurrence and ...