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Building Effective Data Visualizations

Kate M. WatkinsSenior Economist

Colorado Legislative Council StaffNCSL Fiscal Analyst Forum

October 6, 2016

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Image from EURUSD FX Blog:

http://eurusd-fx.blogspot.com/2011/09/proportion-of-eur-by-country-based-on.html

Missing title

Missing source information

Missing labels

Poor resolution

Unpleasant colors

3D?

4Charles Joseph Minard (1869), reproduced in Tufte’s (2001) The Visual Display of Quantitative Information

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Best Practices for Effective Data Visualization

1) Ask: Who? What? Why?

2) Know the data

3) Tell a (true) story

4) Create an analytical tool

5) Strive for ‘graphical excellence’

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Colorado Online Tax Handbookhttp://leg.colorado.gov/agencies/legislative-council-staff/colorado-online-tax-handbook

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Who is your target audience?

What are the goals of the visualization?

– Explanatory: lead your audience to a conclusion

– Exploratory: let your audience explore

What are you trying to communicate? And why?

1) Ask…

Novice Working Knowledge ExpertIntroduction Briefing In-Depth Analysis

AudienceFormat

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2) Know the data

• Become an expert

• Anticipate questions,

know the answers,

build answers into the visualization

• Pilot test your visualizations

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3) Tell a story with data

Charles Joseph Minard (1869), reproduced in Tufte’s (2001) The Visual Display of Quantitative Information

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3) Tell a (true) story with data

• Don’t lie with graphics

From Darrell Huff’s (1954) How to Lie with Statistics. Illustrations by Irving Geis.

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3) Tell a (true) story with data

• Don’t lie with graphics

• Let the data speak for itself

From Darrell Huff’s (1954) How to Lie with Statistics. Illustrations by Irving Geis.

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4) Create an analytical tool

• Provide enough information for replication

– Cite data sources and note data transformations

and anomalies

• Build in supplemental materials

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4) Create an analytical tool

• Provide enough information for replication

– Cite data sources and note data transformations

and anomalies

• Build in supplemental materials

• Provide the data itself

Novice Working Knowledge ExpertIntroduction Briefing In-Depth Analysis

AudienceFormat

14Charles Joseph Minard (1869), reproduced in Tufte’s (2001) The Visual Display of Quantitative Information

5) Strive for ‘graphical excellence’ (Tufte)

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5) Strive for ‘graphical excellence’ (Tufte)

• Eliminate ‘chart junk’

• Maximize the data-ink ratio

Data-ink ratio = Ink used on data

Total ink used

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5) Strive for ‘graphical excellence’ (Tufte)

• Eliminate ‘chart junk’

• Maximize the data-ink ratio

Sparkline

Data-ink ratio = Ink used on data

Total ink used

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5) Strive for ‘graphical excellence’ (Tufte)

• Eliminate ‘chart junk’

• Get rid of the grid

Image reproduced from Tufte (2001: 113).

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5) Strive for ‘graphical excellence’ (Tufte)

• Eliminate ‘chart junk’

• Get rid of the grid

Colorado State Demography Office, October 2015 projections.

300,000 200,000 100,000 0 100,000 200,000 300,000

0 to 4

5 to 9

10 to 14

15 to 19

20 to 24

25 to 29

30 to 34

35 to 39

40 to 44

45 to 49

50 to 54

55 to 59

60 to 64

65 to 69

70 to 74

75 to 79

80 to 84

85 to 89

90 to 94

95 to 99

100+ Male Female

20162018

Colorado Population by Age and Sex

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5) Strive for ‘graphical excellence’ (Tufte)

Image reproduced from Tufte (2001: 117).

• Eliminate ‘chart junk’

• No ducks allowed

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• The modern duck

5) Strive for ‘graphical excellence’ (Tufte)

Image reproduced from the Professional Business Development website (pbi-now.com).

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5) Strive for ‘graphical excellence’ (Tufte)

• Draw the reader in with color

Charles Joseph Minard (1869), reproduced in Tufte’s (2001) The Visual Display of Quantitative Information

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Best Practices: Color

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2) Be aware of the emotion and culturally-specific

connotations of color

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5) Strive for ‘graphical excellence’ (Tufte)

• Draw the reader in with color

• Be aware of red-green colorblindness

Image from: http://enchroma.com/test/instructions/

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Kate M. Watkins

kate.watkins@state.co.us

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