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Show Me the Numbers: Communicating Effectively with ChartsStephen Few, Perceptual Edge

The DAMA International Symposium & WILSHIRE Meta-Data ConferenceDenver, Colorado �April 23-27, 2006

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Show Me the NumbersCommunicating Effectively with Charts

Stephen Few

In 1786, an iconoclastic Scot – William Playfair –published a small atlas that introduced or greatly improved most of the quantitative graphs that we use today.

Prior to this, graphs of quantitative data were little known.



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Today, 220 years later, partly due to the arrival of the PC, graphs are commonplace, fully integrated into the fabric of modern communications.

Surprisingly, however, Playfair’s innovative efforts – sprung from meager precedent – are still superior to most of the graphs produced today.

A powerful language,with such promise,

is largely being wasted!



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Despite a recent explosion in available data, most lies stagnant in ever-expanding pools.

Data is useless until we understand what it means and can clearly communicate that meaning to those who need it, those whose decisions affect our world.

So…here you are today.

You have a choice.

You can demand better.



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Finally…

Effective network monitoring has arrived!

• Near real-time

• Phenomenally user-friendly

• Instant insight � effective response



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“Just show me the numbers!”

We are awash in data.



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Why? Numbers are critical to business.

Right?

We’re getting better at handling numbers –



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Are you sure it isn’t in here?

Do you know where your Business Intelligence (BI) investment is now?

Quantitative information is primarily communicated through tables and graphs.

But few communicate effectively. Why?



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Intentional deceit is no longer our biggest problem

Numbers need never be vague or ambiguous

3+2=??!!#!!!&%***@!



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What happened?

The PC happened!

Numbers are commonly obscured, then

made to look pretty.

Example #1 - Poor



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Example #1 - Good

Example #2 - Poor



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Example #2 - Good

Example #3 - Poor



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Example #3 - Worse

Example #3 - Good



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Example #4 - Poor

Example #4 - Good



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Warning!

Even software vendors encourage poor design

Example: Totals of something or other by year



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Example: Percentage revenue per product line

Example: Revenue by service line



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Example: Purchases by product line and buyer

Example: Profit by part and month



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Example: Revenue by sales channel and quarter

Example: Revenue by product and quarter



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Example: Expenses by GL account category and account

Example: Hotel revenue by service and quarter



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Example: Revenue vs. costs per month

Example: Your guess is as good as mine



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Do the vendors poor examples matter?

Contest Scenario:

This scenario involves the display of departmental salary expenses. It is used by the VP of Human Resources to compare the salary expenses of the company’s eight departments as they fluctuate through time, in total and divided between exempt and non-exempt employees.

Time-Series Solution #1



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Time-Series Solution – One that works



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What do tables and graphs help us do?

“Above all else show the data.”

Edward Tufte

Thinkand

Communicate

Communication problems – whether verbal or visual – are basically the same

I returned, and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favor to men of skill; but time and chance happen to them all.

Ecclesiastes 9:11 (King James version of the Bible)

Objective consideration of contemporary phenomena compels the

conclusion that success or failure in competitive activities exhibits no

tendency to be commensurate with innate capacity, but that a

considerable element of the unpredictable must invariably be taken into

account.

George Orwell’s rewrite of this passage into bloated prose



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The two fundamental challenges of data presentation

1. Determining the medium that tells the story best

2. Designing the visual components to tell the story clearly

0

10

20

30

40

50

60

70

80

90

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

East

West

North

From

toRevenue

0

20

40

60

80

100

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

Year 2003

U.S.$East West North

1,592,36777,211Total

845,98442,374Beverage

746,38334,837Food

RevenueUnits SoldProduct

or

0 20 40 60 80

Marketing

Operations

Finance

Sales

andwhich kind?

Either

Match the display to your message



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Eeney, meeney, miney, moe – what type of display should I use this time?

or

• Used to look up individual values

Tables work best when

• Used to compare individual values

• Data must be precise

• You must include multiple units of measure



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What do graphs do best?

Graphs show relationships between values by giving them shape.

Graphs bring relationships to light

What’s the message?



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Quantitative messages always involve relationships.

Relationship? Time Series

Time



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RankingRelationship?

1

2

3

4

5

6

7

8

Part-to-WholeRelationship?

+ + + =100%



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DeviationRelationship?

DistributionRelationship?



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CorrelationRelationship?

Nominal ComparisonRelationship?



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• Nominal comparison

• Time-series

• Ranking

• Part-to-whole

• Deviation

• Distribution

• Correlation

The seven common relationships in graphs

What’s the other half?

Knowing the right medium is half the battle.

Designing each component to speak clearly.



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The power of visual perception

70% 30%

Visual perception is not just camera work

Square A is darker than B, right?



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We perceive differences, not absolutes

Take a closer look

Context affects visual perception



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Save the pies for dessert!

What about grid lines in graphs?



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What about 3-D? It’s so cute!!!

But what if there’s a 3rd variable?



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Can you ever show too much?

Is more color always better?



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Color choices make a difference

Business intelligence and data visualization

Emphasis on technology Emphasis on human ability



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You have a choice to make!

To communicate

or not to communicate,

that is the question!

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