Find Your Root Cause With Fishbone Diagrams by hkksew3563rd


									?A fishbone diagram is a tool used to facilitate root cause analysis for a defined
problem. The diagram provides a structured way to record potential root causes
during brainstorming, encouraging teams to think about a problem systematically and
to dig deeper to discover less obvious causes.

The fishbone model, a kind of cause and effect chart, was originated by a quality
control professional from Japan named Dr. Kaoru Ishikawa. Hence the other
nickname for this diagram, the "Ishikawa Diagram." It is commonly referred to as a
"fishbone" model because in appearance it is similar to the skeletal structure of a fish.

The "backbone" of the fishbone diagram is a horizontal line that divides the paper in
two. The analysis starts with a problem to be investigated. On the right side of the
page the problem is written in the form of a question. Sometimes a drawing of a fish
head or an arrow will point to the question under consideration.

The following collection of bones stand for the primary types of variables that might
play a part in the underlying or root cause. The labels of these subsets are displayed
across the upper and lower portions of the page. Arrows lead in the direction of the
spinal column and in the direction of the head, creating a herringbone look.

Conventions have developed to provide starting categories appropriate for different
types of problems domains. In manufacturing, the 6 M's are used: Machine, Methods,
Materials, Maintenance, Man, and Mother Nature. Modern analysis of manufacturing
problems adds categories like: Equipment, Process, People, Materials, Environment,
and Management. The 8 P's are a useful starting point for analysis of service and
administrative problems: Price, Promotion, People, Processes, Place / Plant, Policies,
Procedures, and Product. A service industry may also use the 4 S's: Surroundings,
Suppliers, Systems, and Skills.

Analysis gets underway after the fundamental skeletal structure is in position.
Variables are listed that play a part in each subset of elements that result in the
underlying or root cause. These are displayed on top of arrows directing you to the
subset lines, which themselves may possess lines of their own directing toward them,
further delineating the variables that play a part. While this may proceed ad infinitum,
naturally it will be hard to sketch more than a minimal number of levels.

The reasons which causes the end result is analyzed by a team through brainstorming
each category, using the skeleton of the diagram. With reference to the context of each
category, a question is formed according to the problem and asked the team members
to answer them. Generally questions like "why this is happening" is asked and
according to the category the question varies to "How do factors influence this

The brainstorming continues until team members can no longer think of useful items
to add to the diagram. At this point, the results are analyzed to identify the most likely
root causes of the problem. Finding the same issue within multiple categories is a
good indication that it is an important root cause in the system. Likewise, areas of the
diagram that are densely populated with detail are likely to point to areas of

Steve Wilheir is a project manager. Learn more about the fishbone chart and fishbone
diagram and how to conduct a fishbone analysis of your organization's teamwork

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