Ishikawa Fishbone Diagram Helps Determine Cause and Effect
You’ve heard the same complaint over and over: “The problem is
we need more people!” Ok… no. The problem isn’t that you need
more people. The problem may be that all of the mail isn’t
getting delivered by 5:00 pm. That may be a problem. One of the
reasons, or causes, or the delay in delivery is that you may be
in the midst of a hiring freeze and therefore you don’t have as
many mail carriers as you used to. However the problem is not
that you need more people. The problem is also not that you need
more money or that you need more time. Those are not problems.
One way to find the problem to any given situation, so that you
are better equipped to find a viable solution to the problem, is
to construct a fishbone diagram. Other names for the same
graphical depiction are called Ishikawa Diagram, Root Cause
Analysis or Cause and Effect Diagram. This tool was named after
the inventor, Kaoru Ishikawa who first used the technique in the
1960s.
The purpose in using a fishbone is to arrive at a handful of main
causes that contribute most significantly to the problem being
examined. These causes are then targeted for improvement. The
diagram also shows the relationships between the wide ranges of
possible contributors to the effect.
When you’re done constructing your diagram, it will look like a
fish carcass, thus the name fishbone diagram. The problem that
you’re targeting will be in a box, or the head of the fish to the
far right of your paper. Then you’ll draw a horizontal line cross
the page. Off of the horizontal line, you’ll draw four vertical
diagonal lines (bones) which will each represent a different main
grouping or cause category. Two will protrude on top of your
horizontal line and two will fall below the line.
Label each of the bones with the following titles: Manpower,
Materials, Machines and Methods. These will serve as
springboards for you to further delve into each cause. For
example, under Manpower – this is where your staffing issues are
listed. Perhaps you’ll add a small horizontal bone coming off
this one that says ‘hiring freeze’ and another bone labeled
‘training’. Continue on with the next bone. Under Machines –
you could have “bar code sorter rejects” then “not enough
techs”.
Pretend you are a three year old and keep asking WHY? Rule of
thumb is to ask “Why?” five times for each category. Carriers
don’t return to the office until 6pm. Why? (#1) Because we don’t
have enough to cover the routes. Why? (#2) Because some have
retired and we can’t hire more. Why? (#3) There’s a hiring
freeze. Note: Going further on the hiring freeze may not help if
that decision is beyond your span of control. Therefore, switch
gears if you truly have no authority to change a situation.
Sometimes carriers aren’t getting back until dark because they
have to pivot and help other routes, Why? (#4) Because the new
carriers are slow. Why (#5) because they’re not getting out of
the office until 1300, so there’s no way they can get back by
1700. Ok stop. Now you have a definitive situation to review,
brainstorm and find a solution.
Now your problem may have just become: New carriers aren’t
leaving for the street until 1300. Then you can repeat the above
process and dig deeper until you can find the TRUE root cause.
Then fix your problem. Many times managers fix problems that
aren’t broken. Only to find their original problem still
exists.
Keep these tips in mind when creating your Ishikawa:
1. Place the main problem you’re trying to solve in a box on the
right, for the fish’s head.
2. This tool works alone or in team settings. Generate and
clarify all the potential sources of variation.
3. Sort your possible causes into naturally related groups. (Use
manpower, machines, materials and methods as your guide when
grouping them). The labels of these groups are the names for the
major bones on the Ishikawa diagram.
4. Place all the causes that you’ve just brainstormed on the
appropriate bones of the diagram.
5. Ensure that the causes are specific, measurable, and
controllable. Meaning if you can’t measure progress or defects
or if you don’t have span of control to do something about it,
select another cause that you can actively work to rectify.
As you find solutions to little problems, continually rework your
diagram. You’ll be amazed at the small incremental steps you’ll
make at improving your overall operations. This visual depiction
of the problems will help you stay focused on true root causes
and solutions. No longer will you operate off complaints such as
“The problem is we don’t have enough people!”
Author
George Whitecraft
http://whitecraftshoppingmarketing.biz/tbp/The_Business_Professional.html
http://whitecraftshoppingmarketing.biz/pba/index.htm
posted by George @ 12:50 PM
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