Emerging Tech

Use a Fishbone Diagram to attack complex problems

One technique for analyzing complex problems that appear to have many interrelated causes is called a "cause and effect" diagram or a Fishbone Diagram. Here are examples of how this problem-solving technique works.
Editor's note: This article was originally published July 14, 2006.

Problems arise on many projects. A proactive project manager should have a set of problem resolution techniques that can be applied in different instances. One technique for analyzing complex problems that appear to have many interrelated causes is called a "cause and effect" diagram. Because of its shape, this technique is also called a Fishbone Diagram. (Another name you might hear for this technique is an Ishikawa Diagram. This is named for Professor Kaoru Ishikawa, a Japanese professor who pioneered the diagram in 1943.) Some benefits of a Fishbone Diagram include:

  • It allows various categories of causes to be explored.
  • It encourages creativity through a brainstorming process.
  • It provides a visual image of the problem and potential categories of causes.

The following description and examples show how the problem-solving technique works.

First, describe the problem on the far right side of the diagram. This may be the actual problem or it may be a symptom -- at this point you're not exactly sure.

Draw a long horizontal arrow pointing to the box. This arrow will serve as the backbone from which further major and minor causes will be categorized and related. (See Figure A.) Figure A

Figure A

Identify potential causes and group them into major categories along the "bones" of the Fishbone Diagram. You should brainstorm to identify the major categories; at this point, you shouldn't be concerned if there's disagreement about whether a category holds the potential cause -- just put them all up. Make sure to leave enough space between the major categories on the diagram so that you can add minor detailed causes in later. (See Figure B.) Figure B

Figure B

Continue to brainstorm the causes by looking at more detailed explanations for each of the major cause categories identified above. The team should ask whether each category is a cause, or if it is a symptom. If it's a symptom, try to identify the more detailed causes on slanted lines that hook up to the appropriate major category lines. (See Figure C.) Figure C

Figure C

Sometimes, the detailed causes will have other, more granular causes coming off of them. If so, connect additional lines to the detailed lines. Three levels of detail is usually the practical limit for this diagram.

When you finish brainstorming major causes/symptoms and more detailed causes and symptoms, the team can begin analyzing the information. Evaluate each major cause and the potential detailed causes associated with it. Remember that the original list was compiled by brainstorming where all ideas are included. Now, you must determine which items seem more likely to be the cause (or one of the causes). Circle the items that are most likely and need to be investigated further.

If there's not an obvious consensus on the top areas to investigate, use some sort of voting system to formally narrow down the top choices with the biggest chance of success. For each item circled, discuss how the item impacts the problem.

Once you circle the causes that appear to be the most likely, you should create an action plan for attaching these causes. This will most likely involve some high-level actions and assigning the cause to a team member to be analyzed outside of the meeting.

Remember that this technique is used for complex problems with multiple causes and allows you to identify potential causes for the problem and determine which ones are most likely to be resolved.

19 comments
vlad_s
vlad_s

I really don't understand why this trivial mean arouses such sensational response. Fishbone per se it's just the list of factors. Even same may be done by multi-level bullets in, e.g, MSWord. In real life we have many reasons of the problem, and all of them connected with each other in different types of relationship.

donstrayer
donstrayer

An Ishikawa diagram (a.k.a. fishbone or cause and effect diagram) is a proven, simple technique for discovering root and common causes. But it does not help you to prioritze correcteive actions. The tool I prefer for that is FMEA (Failure Mode Effects Analysis). This is basically a spreadsheet that you populate with the items from the fishbone and then weight impact, likelihood of occurrence, and detectability. It calculates an RPN (Risk Priority Number). Examples are easy to find via web search. It's easier than it looks at first glance.

heffner
heffner

I agree with previous comment that mindmap or freemind (freeware) are excellent for doing same thing but on computer. Fishbone diagrams are what I have found useful when I'm working at a board or easel, though. Might note that in my experience, you should not hesitate to add bones off of bones off of bones.... and don't worry about the angle you have to take. Just run the new bone out away from the "crowd" in order to be able to put more bones on it as well. Second comment, to me (my pref.) the bones should always "angle" away from the bone they are coming off of, but not against the grain. In the example the little horizontal bones off of the initial 4 bones threw me. I would have angled them of their "parent" in the opposite direction as shown, always away from any "ancestor" bones. (Sorry that you have to imagine what is in my mind)

jeraldj
jeraldj

Yes we agree, but a Case Study with how this diagram helped, could make us envisage it better .....

harriden.agri
harriden.agri

This is a great resource. Can the Fishbone Diagram be used for WBS?

kandiamo
kandiamo

I use fishbones for every problem: moving,job-hunting, home repair, work, talking with my boss about a sensitive subject. I circle the most important problems, number the order things need to get done and then cross out the branch that's finished or irrelevant. It's a great way to cut through complexity of some problems so real issues can be knocked off one by one.

NotSoChiGuy
NotSoChiGuy

The first time someone proposed we use a Fishbone to address a problem (I want to say it was for system deployments), I thought they were out of their mind. I was certain a game of Pictionary was next on the agenda. By the end of the week (meeting occurred on a Tuesday), I was a convert. Combining this with the 80/20 principle, you can really push through effective change; assuming everyone is on board.

james.tallman
james.tallman

Excellent timing. This week we are researching different tools to employ during root-cause analysis meetings for ITIL Problem Management. This is a easy to understand explanation of what a Fishbone diagram is and how to construct one. Thanks

deeanne34
deeanne34

I use Mindjet's MindMap Pro to do this type of brainstorming to capture ideas. It is super easy to learn and allows for export into other applications.

galleman
galleman

One approach to using the information from the diagram, is to build a Mind Map. Then the "map" can be turned directly into a project plan to address the causes of the issue.

rodbell101
rodbell101

Good blog--but there is duplication! The 5 paragraphs under Figure C are duplicated. As for content, I like it, but it appears that it would work best (for me) as a personal heuristic. It looks like it would go haywire in a brainstorming environment; at any rate, I don't see how I'd manage that, since brainstormers won't necessarily see major/minor very well in the moment.

RikDee
RikDee

...I like it. Thanks, I think I'll use it!

rm_godinez
rm_godinez

Fishbone diagrams are extremely useful. The team involved should take an open mind in using this extremely simple tool to list down the various causes.

alex.kashko
alex.kashko

Looks like a restricted version of mind mapping to me. If using paper and pencil I use mind maps. Well sort of, I tend to modify the concept slightly as needed. Electronically I use a neat piece of freeware called Compendium, which is a concept mapping tool. I've used that for a lot of things.

konka_kiran
konka_kiran

I Liked it...I'll be using it to solve my problems

Editor's Picks