Post on 01-Jan-2016
Don’t Hide Good Data Analyses in Difficult Graphs
Gary McClelland & Julie SchiroAnalyze Boulder
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Florence Nightingale
“The Passionate Statistician”
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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John Snow
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Charles Minard
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
54 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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A B C D0
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Blue
Red
Green
3D Column Chart
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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“Height of Green Columns”
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Blue > Green
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Both Answers Correct?
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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A B C D0
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Blue
Red
Green
Green Columns = 5
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Same data in 2D
A B C D0
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4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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But even here…
A B C D0
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High contrast where not needed
Low contrast where discrimination needed
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Scatterplots from R
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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However
DOTS
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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What is the Relationship?
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
164 June 2014
Not at all worth it
Very worth it
Neither helpful nor hurtful
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Identical graphs, except the red cluster appears in the lower left or upper right
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Without red clusters - identical
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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With “red” clusters
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Regression Line Helps
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Punchlines
• “It’s not you, it’s me”: If the decision maker can’t understand your graph, don’t blame the decision maker. Make a better graph.
• Unless there really is a 3rd dimension that you really need to display, avoid 3D graphs.
• Enhance scatterplots and other graphics from stat programs to help the viewer focus on all of the data, not just some of it.
4 June 2014
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
224 June 2014
May you make great graphs!
Thank you!
Gary & Julie
gary.mcclelland@colorado.edu & julie.schiro@colorado.edu
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Useful Links & Addresses• Gary.mcclelland@colorado.edu• Julie.schiro@colorado.edu• Gary’s ground-breaking but now aging online interactive statistics textbook using
Java applets: http://www.seeingstatistics.com• Gary’s data analysis textbook: http://www.dataanalysisbook.com• Gary’s data visualization consulting firm: http://www.bolderstats.com• Java applets for teaching statistical concepts:
http://www.seeingstatistics.com/gallery/ [the magic words are ‘model’ and ‘error’]• Steven Johnson’s TED talk about John Snow’s “ghost map”:
http://www.ted.com/talks/steven_johnson_tours_the_ghost_map.html• Michael Friendly’s data visualization website, the “Milestones Project” describes
and illustrates the ‘Golden Age of Data Graphics’: http://www.datavis.ca• Edward Tufte is usually considered the guru of modern data graphics. His website
has LOTs of resources: http://www.edwardtufte.com/tufte/• This presentation: http://www.bolderstats.com/graphsAB.pptx
4 June 2014