effective data visualization (david giard)
DESCRIPTION
We spend much of our time collecting and analyzing data. That data is only useful if it can be displayed in a meaningful, understandable way. Yale professor Edward Tufte presented many ideas on how to effectively present data to an audience or end user. In this session, I will explain some of Tufte's most important guidelines about data visualization and how you can apply those guidelines to your own data. You will learn what to include, what to remove, and what to avoid in your charts, graphs, maps and other images that represent data." "We spend much of our time collecting and analyzing data. That data is only useful if it can be displayed in a meaningful, understandable way.TRANSCRIPT
David Giard
Microsoft Technical Evangelist
blog: DavidGiard.com
tv: TechnologyAndFriends.com
twitter: @DavidGiard
Data VisualizationThe Ideas of Edward Tufte
@DavidGiard
This presentationis dedicated to
Dave Bost
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I II III IV
x y x y x y x y
10.0 8.04 10.0 9.14 10.0 7.46 8.0 6.58
8.0 6.95 8.0 8.14 8.0 6.77 8.0 5.76
13.0 7.58 13.0 8.74 13.0 12.74 8.0 7.71
9.0 8.81 9.0 8.77 9.0 7.11 8.0 8.84
11.0 8.33 11.0 9.26 11.0 7.81 8.0 8.47
14.0 9.96 14.0 8.10 14.0 8.84 8.0 7.04
6.0 7.24 6.0 6.13 6.0 6.08 8.0 5.25
4.0 4.26 4.0 3.10 4.0 5.39 19.0 12.50
12.0 10.84 12.0 9.13 12.0 8.15 8.0 5.59
7.0 4.82 7.0 7.26 7.0 6.42 8.0 7.91
5.0 5.68 5.0 4.74 5.0 5.72 8.0 6.89
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Dr. Edward Tufte
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Graphical Excellence
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500,000
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Graphical Integrity
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Blatant Lies
Source: Fox News, Dec 2011Reprinted by Washington Post
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$(11,014)$0 $(11,014)
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Lie
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Lie Factor
𝑆𝑖𝑧𝑒 𝑂𝑓 𝐸𝑓𝑓𝑒𝑐𝑡 𝑆ℎ𝑜𝑤𝑛 𝐼𝑛 𝐺𝑟𝑎𝑝ℎ𝑖𝑐
𝑆𝑖𝑧𝑒 𝑂𝑓 𝐸𝑓𝑓𝑒𝑐𝑡 𝐼𝑛 𝐷𝑎𝑡𝑎
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Lie
Data Increase = 53%
Graphical Increase = 783%Lie Factor=14.8
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Truth
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1978 1979 1980 1981 1982 1983 1984 1985
Required Fuel Economy Standards:New cars built from 1978 to 1985
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Data Change = 125%
Graphical Change = 406%Lie Factor=3.8
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Data Change = 554%
Graphical Change = 27,000%Lie Factor=48.8
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Context
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1955 1956
Connecticut Traffic Deaths,Before (1955) and After(1956)
Stricter Enforcement by the PoliceAgainst Cars Exceeding Speed Limit
Before stricterenforcement
After stricterenforcement
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1951 1952 1953 1954 1955 1956 1957 1958 1959
Connecticut Traffic Deaths1951-1959
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1951 1952 1953 1954 1955 1956 1957 1958 1959
Traffic Deaths per 100,000Persons in Connecticut, Massachusetts, Rhode Island, and New York1951-1959
NY
MA
CT
RI
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Principles of Graphical Integrity
• Data Representations proportional to Data
• #Dimensions in graph = #Dimensions in data
• Real dollars, instead of deflated dollars
• Provide context
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Data-Ink
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Data-Ink Ratio
= 𝐷𝑎𝑡𝑎 𝐼𝑛𝑘
𝑇𝑜𝑡𝑎𝑙 𝐼𝑛𝑘
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Redundant Data
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Metadata
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Principles
• Above all else, show the data
• Maximize the Data-Ink ratio, within reason
• Erase non-data-ink
• Erase redundant data-ink
• Revise and edit
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Vibrations
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Vibrations
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ISSUE AREAS
INFLATION
UNEMPLOYMENT
SHORTAGES
RACE
CRIME
GOVT. POWER
CONFIDENCE
WATERGATE
COMPETENCE
Linear (RACE)
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INFL
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Chart Junk and Ducks
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Worst. Graph. Ever.
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Year % Students < 25
1972 28.0
1973 29.2
1974 32.8
1975 33.6
1976 33.0
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Multifunctioning Graphical Elements
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Data Density
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Data Density
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑒𝑛𝑡𝑟𝑖𝑒𝑠 𝑖𝑛 𝑑𝑎𝑡𝑎 𝑚𝑎𝑡𝑟𝑖𝑥
𝐴𝑟𝑒𝑎 𝑜𝑓 𝐷𝑎𝑡𝑎 𝐺𝑟𝑎𝑝ℎ𝑖𝑐
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Low Data Density
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Low Data Density
Number of entries = 4
Graph Area = 26.5 square inches
Data Density = 4 𝑑𝑎𝑡𝑎 𝑒𝑛𝑡𝑟𝑖𝑒𝑠
26.5 𝑠𝑞. 𝑖𝑛.
=.15 data entries per sq. in.
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High Data Density
181 Numbers per square inch
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High Data Density
1,000 Numbers per square inch
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Small Multiples
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Small Multiples
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Small Multiples
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Tufte’s Graphs
• Sparkline
• Slope Graph
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Sparklines
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Sparklines
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Slope Graph
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Slope Graph
Source: The Atlantic, June 30, 2012
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Takeaways
• Maintain Graphical Integrity
• Maximize Data-Ink Ratio, within reason
• Avoid Chartjunk and Ducks
• Use Multifunctioning Graphical Elements, if possible
• Keep Labels with data
• Maximize Data Density
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Temperature ( C )
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David Giard
Microsoft Technical Evangelist
blog: DavidGiard.com
tv: TechnologyAndFriends.com
twitter: @DavidGiard
@DavidGiard
@DavidGiard