C A R L H A L V O R S O NS R . P E R F O R M A N C E A U D I T O R

C I T Y A N D C O U N T Y O F D E N V E R

Data Visualization

There are many true statements about complex topics that are too long to fit on a

PowerPoint slide.–Edward Tufte

2

The Value

Simplicity is the ultimate sophistication.

Anonymous

3

The Value

4

How Many 7s?

153815892464249516754372323514231753182731345485684568598631235138165323521853514015243015405318184568792015648042316

5

How Many 7s?

153815892464249516754372323514231753182731345485684568598631235138165323521853514015243015405318184568792015648042316

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Lines, Bars, Pies….Stress

Color

SizeGr ou pin g

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3 Things to Think About

1. Present the data that matter. 2. Tell a story, simply. 3. Choose an appropriate visual.

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Present the Data That Matter

Ask: What is the big picture? What matters most? Is there too much information? Is there inconsistent ordering and placement?

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Avoid CHARTJUNK

0.5

0.6

0.7

0.8

1-Feb15-Feb

1-Mar

15-Mar

29-Mar

USD /EUR

USD /GBP

10

0.55

0.6

0.65

0.7

0.75

0.8

Rat

eExchange Rates - USD/EUR; USD/GBP

2/1/14-3/31/14

USD / EURUSD / GBP

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Example

Arrests in 2014 by Charge ‐‐16th Street MallCharge Number of Arrests

Theft 383

Drug Alcohol/Marijuana 341

Warrant/Violation Court Order 297

Trespassing 170

Panhandling 128

Other 112Failure to Obey 56

Source: Denver Post

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Tell a Story, Simply

Never underestimate your audience. Ask: What do you need to know from your data? Why do you need to know it?

What do you want your audience to know from your data? Is it relevant?

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Choose an Appropriate Visual

Ask: What is it you

are trying to convey?

383Theft

341Drug/Alcohol/Marijuana

297Warrant/Violation Court Order

170 Trespassing

128 Panhandling

112 Other 56 Failure to Obey

Arrests in 2014 by Charge – 16th

Street Mall

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0 100 200 300 400

Theft

Drug Alcohol/Marijuana

Warrant/Violation Court Order

Trespassing

Panhandling

Other

Failure to Obey

Number of Arrests in 2014 by Charge --16th Street Mall

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If a diagram is worth 1000 words, then it’s worth 1000 words of our

attention.

–Edward Tufte

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Less is More

383 arrests

341 arrests

297 arrests

170 arrests

128 arrests

112 arrests

56 arrests

0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450

Theft

Drug Alcohol/Marijuana

Warrant/Violation Court Order

Trespassing

Panhandling

Other

Failure to Obey

Number of Arrests in 2014 by Charge --16th Street Mall

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Pie Charts

Arrests in 2014 by Charge --16th Street Mall Number of Arrests

Theft

DrugAlcohol/MarijuanaWarrant/ViolationCourt OrderTrespassing

Panhandling

Other

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Pie Charts

Arrests in 2014 by Charge --16th Street Mall Number of Arrests

Theft

DrugAlcohol/MarijuanaWarrant/ViolationCourt OrderTrespassing

Panhandling

Other

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Don’t end up presenting-“… a riddle, wrapped in a mystery,

inside an enigma.”

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Further Information

“Envisioning Information” – Edward Tufte “Data Visualization” – Edward Tufte “Beautiful Visualization” – Julie Steele “Show Me the Numbers” – Stephen Few

Thank you!