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TABULATING AND GRAPHING DATA

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“Graphical excellence consists of the efficient

communication of complex quantitative ideas.”

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TABULATION

According to Connor, "Tabulation involves the orderly

and systematic presentation of numerical data in a form

designed to elucidate the problem under consideration.“

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PARETO DIAGRAMS

No Signature Illegible Current Customer No Address Other0

5

10

15

20

25

30

35

40

45

0%

20%

40%

60%

80%

100%

120%

Frequency

Cumulative %

Fre

qu

ency

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CONTENTS

• What Is A Pareto Chart?

• Why A Pareto Chart Be Used?

• When Should A Pareto Chart Be Used?

• How Is A Pareto Chart Constructed?

• Steps To Construct A Pareto Chart Manually

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PARETO DIAGRAMS

WHAT IS A PARETO CHART?

The Pareto Chart is named after Vilfredo Pareto, a 19th

century economist who postulated that a large share of

wealth is owned by a small percentage of the

population.

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Cont…

A Pareto Chart is a series of bars whose heights reflect

the frequency or impact of problems. The bars are

arranged in descending order of height from left to

right.

Pareto charts are extremely useful because they can be

used to identify those factors that have the greatest

cumulative effect on the system, and thus screen out the

less significant factors in an analysis. 8

WHY A PARETO CHART BE USED?

• In most systems, quality related problems are owing to

numerous factors, the Pareto Principle which states that

80% of the problems come from 20% of the Causes.

• A Pareto Chart breaks a big problem down into smaller

pieces, identifies the most significant factors, shows where

to focus efforts, and allows better use of limited resources.

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WHEN SHOULD A PARETO CHART BE USED?

A Pareto Chart is a good tool to use when the process you

are investigating produces data that are broken down into

categories and you can count the number of times each

category occurs.

A Pareto diagram puts data in a hierarchical order, which

allows the most significant problems to be corrected first.

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HOW IS A PARETO CHART CONSTRUCTED?

• To construct a Pareto Chart, you need to start with

meaningful data which you have collected and

categorized.

• You need to segment the range of the data into groups

(also called segments or categories).

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Cont…

For example, if your business was investigating the delay

associated with processing credit card applications, you

could group the data into the following categories: No

signature, Residential address not valid, Non-legible

handwriting, Current customer, and Other.

You may either construct a Pareto Chart manually or

with Excel.

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STEPS TO CONSTRUCT A PARETO CHART MANUALLY

Record the raw data. List each category (i.e., No

signature, Residential address not valid, Non-legible

handwriting, Current customer, and Other) and its

associated data count (how many times each category

occurred) and the place data in descending order.

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Delay in Processing Credit Card Application

Category Frequency Percentage Cumulative %

No Signature

Non-legible handwriting

Current Customer

Residential address not valid

Other

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Delay in Processing Credit Card Application

Category Frequency Percentage Cumulative %

No Signature 40

Non-legible handwriting

22

Current Customer 15

Residential address not valid

9

Other 8

94

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Delay in Processing Credit Card Application

Category Frequency Percentage Cumulative %

No Signature 40 43%

Non-legible handwriting

22 23%

Current Customer 15 16%

Residential address not valid

9 10%

Other 8 9%

94 100

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Delay in Processing Credit Card Application

Category Frequency Percentage Cumulative %

No Signature 40 43% 43%

Non-legible handwriting

22 23% 66%

Current Customer 15 16% 82%

Residential address not valid

9 10% 91%

Other 8 9% 100%

94 100

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No Sig

nature

Illeg

ible

Current C

ustom

er

Resid

entia

l add

ress

not va

lidOth

er05

1015202530354045

0%

20%

40%

60%

80%

100%

120%

Delay in Processing Credit Card Application

Frequency Cumulative %

Fre

qu

ency

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CONCLUSION

• No matter how may data are categorized, they can be

ranked and made into a Pareto diagram. Sometimes,

no single bar is dramatically different from the others,

and the Pareto Chart looks flat or gently sloping.

• To attack the tall bar in that situation is no help. You

need to look for another way to categorize the data.

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• “There remain, however, many other considerations

in the design of statistical graphics – not only of

efficiency, but also of complexity, structure, density,

and even beauty.”

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