
Pareto Chart You Say?
One of your department heads looks at
you and asks Ishiwhat? You know, you reply, a fishbone
diagram. Still blank stares. Cause and effect? you
say as you scribble out a trout carcass on your white
board. Still nothing. Youre starting to think the
elevator doesnt go all the way to the top. Youve got
your work cut out for you. So you decide to punt.
Ok, lets just start with the Pareto charts, you concede.
Sir, what is a potato chart? asks another supervisor.
Lets take a five minute stretch break and then meet
back in here so that I can welcome you to the world
of Pareto charts.
A Pareto chart looks similar to a bar
chart. It has columns and it also has a line graph.
Generally number of occurrences (frequency) is listed
on the left side and percentage on the right. This
type of chart is used to graphically summarize and
display the relative importance of the differences
between groups of data. For example, perhaps you have
determined, or at least speculate that your widgets
are being rejected due to improper fittings, defective
sorting machine, too large or too small, or other.
If you look at the reports or studies and gather data
on each of these reasons for failure, you can then
plug the numbers into a chart. You may have assumed
the reason for rejection was because the widgets were
too large to fit through the tunnel. However your
numbers may actually show (the data will validate)
that indeed there was nothing wrong with the size
of the widget, but rather the sorter was bent, thereby
causing the good pieces to bounce into the reject
bin.
Typically you isolate five categories
to measure. A Pareto chart can be constructed by separating
the data into categories. Lets look at another example.
If your business was investigating the delay associated
with processing mortgage applications, you could group
the data into the following categories: No signature,
address not valid, illegible handwriting, existing
customer and other.
The left-side vertical axis of the Pareto
chart is labeled Frequency (the number of counts for
each category), the right-side vertical axis of the
Pareto chart is the cumulative percentage, and the
horizontal axis of the Pareto chart is labeled with
the group names (categories) of your response variables.
Are you getting the idea? Your bottom row will be
labeled: No signature, address not valid, illegible
handwriting, existing customer and other. Each title
will have a corresponding column associated with it.
Next determine the number of data points
that reside within each group and construct the Pareto
chart in a spreadsheet program; Excel works very well
for these types of charts. The difference between
a Pareto and a typical bar chart is that the Pareto
chart is ordered in descending occurrence importance.
Once you have your Pareto constructed
and you can visually see what the data is telling
you, and you will be able to answer a few questions.
You will be able to determine the largest issues facing
your team, department or business; you will be able
to see what 20% of sources are causing 80% of the
problems; and lastly you will know where you should
focus your efforts to achieve the greatest improvements.
No more guess work. You wont be needlessly
wasting more time and money trying to fix problems
that werent broken. Call a staff meeting and get to
work on your potato, er a Pareto Charts!
James Louis writes about things that
impact our society. His years of experience in finance
prompts him to write about and share his insights
about different aspects of the financial world. One
of those insightful subjects is Forex trading. For
more information visit his Forex site.