fishbone diagram notes #1

8/13/2019 Fishbone Diagram Notes #1

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Creating A Cause-and-Effect Diagram

When creating a "fishbone" diagram, each "vertebrate" is a section of one of 6

Basic categories. Once a main "fishbone" with six "bones" is created, each

individual "bone" or section, can then be broken down further into another"fishbone" of individual items for analysis. The 6 basic categories are easily

remembered from the anagram "5 ME". These basic categories are:

1. MAN - Does the operator have the proper training, experience, and ability toperform the function?

2. METHOD - Are the work instructions available and up-to-date? Do theyreflect the best method to perform the task? Are the proper tools available?

Are the process parameters specified clearly?3. MACHINE - Does the machine have the capability to produce the product as

specified? Does the machine have the ability to produce the product on aconsistent basis? Are there regular routine maintenance and preventative

maintenance tasks? Are they performed according to schedule?

4. MATERIAL - Are the correct materials available for the process? What isthe quality of the material used in the process? Is there more than onesupplier and does quality vary with different suppliers? What types ofmaterial problems could exist?

5. MEASUREMENT - Are the measurement instruments adequate for theprocess? Are they maintained correctly and regularly calibrated? Are themeasurement instruments affected by environmental conditions such as

temperature, vibration, dirt, etc.?


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6. ENVIRONMENT - Is the manufacturing environment affected bytemperature, humidity, dust and dirt, power fluctuations or seasonaldifferences?

It is worth noting that within the measurement category, there can be variances.For example, the way one individual handles calipers and measures may differfrom the next individual. It is important to have a training class for those who

measure, to make the method of measurement consistent between all operators.Inconsistent measurement techniques can often lead you to believe that there are

problems in the process that may not actually exist.

Steps to Making a Team Cause-and-Effect Diagram

Again I recommend reviewing the Team Dynamics Introduction at the beginning

of this web site. While one person can sit down and construct a "fishbone" diagramand go through the functions, it is wiser to form a team to "brain storm" the

process. Gathering a cross-functional team of 4 - 7 individuals is the best and

recommended process. It is also useful to include a "neutral" person who is not

familiar with the process. The reason for that is this person will try to familiarizethemself with the process, and in doing so, ask many questions that may spark an

idea amongst the group. This neutral person may also present ideas and viewpointsthat others may not consider.

Appoint someone to be in charge of drawing the diagram. It is recommended that

you use either a drawing board, a flip chart, or gather some large poster paper todraw the diagram on. You may also utilize "Post-It" Notes on a wall, if none of the

above items are available, laying those post-its out in a fishbone arrangement.Whatever method you choose, it should be available for all to see.

GETTING STARTED

1. First, formulate the problem and write it in a box on the right side of the

diagram. Everyone must clearly understand the nature of the problem and theprocess/product being discussed. If everyone is not clear on the purpose of thesession, the session will not resolve the problem.

2. Next, draw an arrow from the left side of your chart or board, over to the rightside and make and arrowhead point. To the right of the arrowhead, place your


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"problem" topic. This arrow is called the "EFFECT" arrow.

3. Now place your main "fishbones" in place, the "5 M's" and the "E", laying it

out as in the example chart above. If using a drawing board or flip chart, draw the

slanted lines in place and label them, spacing each slanted "bone" apart so as to beable to place smaller "bones" on the main bones. Once your chart is prepared, youare ready to begin the "brain storm" session.

Once prepared, your chart will begin to look something like this:

It is important to prepare your group with the main theme that "NO IDEA ORTHOUGHT IS STUPID!" Every idea should be presented, anything that pops into

anyone's head should be brought out. Even if the one idea is not seen asappropriate to the group, it could very well trigger another thought or idea in

someone else. Thus, it is imperative that you have your group understand, thatthere are no silly thoughts, no suggestions that should go unconsidered andeveryone's ideas and input are needed.

4. The "brain storm" session should begin by discussing one of the main "bones"or categories individually. You need to get the group to focus on one category so

as to consider every possible cause related to the one category. Should an idea

develop that may not fit the category you are in, write it down and place it to the

side for consideration and classification later. It is not good to stop and dwell longon one thought too long as other creative thoughts will be lost.


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5. Once all ideas have exhausted on the one "bone", the group should move on

to the next "bone. Sometimes, someone will have an after thought on the previous

topic. This idea should be recorded and placed on the chart, then immediately

return to the current category. To keep an orderly flow, do not allow members to

jump all around the fishbone, instruct team members that if they have thoughts ona topic not yet being covered, to write that thought down on paper and bring upwhen that topic is discussed.

6. Once all of the categories or "bones" have been discussed and all ideas have

been exhausted, the group now has to decide which may be most relevant to theproblem being considered. The group now needs to decide which cause may be the

most likely contributor to the problem. There are those who say that you should

"cross-out" the ones deemed irrelevant, however, those thoughts could be useful in

a future discussion of a different problem. Therefore, you should put a star, red dot,

or whatever method you choose to highlight those causes the group has decided aremost relevant to the problem. Do not destroy the other thoughts!

7. On a separate page, chart, or off to the side, it is time to prioritize the probablecauses selected. Place either an "A" or number "1" by those that everyone agrees is

a top cause of the problem. Place a "B" or "2" by those everyone feels may not be amost likely cause, but may have some significance. Place a "C" or "3" by those

ideas that might be "unsure" or less likely to be a primary cause.

8. Now take the primary "A's" or "1's" and list those out as the primary reasons

and now decide what activities could be taken to remedy the problem areas. It may

be that more data must be collected, or more investigation into the cause would beneeded before applying an action. The point is, you now have a starting point as towhat the main causes could be, and ACTION ITEMS can be assigned.

9. Before the group disbands, action items should be assigned along with thosepersons responsible for the actions. Agree to meet again at a specified time and

date to discuss and review actions taken. Data should be again collected todetermine if the action put in place has resolved the problem.

10. DO NOT DESTROY any of the materials collected. All of the informationand ideas should be gathered and stored for future reference and problem solving

activities.

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