Common mistakes in data visualization Amedee Van Gasse BarCampGhent3 19 December, 2009
$ whoami <ul><li>Current day job:
MS Office/VBA specialist
Desktop & Mail Security (Antivirus, Spam,...)
Geek stuff:
Ubuntu tweaking
Drupal ( http://foutparkeerders.be  - with  @peterdedecker )
Tik vzw ( http://tik.be )
[email_address] http://amedee.be http://twitter.com/amedee http://be.linkedin.com/in/amedee http://facebook.com/amedee.van...
The power of data visualization <ul><li>Chinese proverb:  One Picture is Worth Ten Thousand Words
The Fast-Food Information Age
Pr0n for the stats junk </li><ul><li>Pointy-Haired Boss
Twitter: Infograph of the day ( @bnox ) </li></ul></ul>
What Makes Good Information Design? <ul><li>Interestingness
Function
Form
Integrity </li></ul>
With Great Power... <ul><li>... Comes Great Responsibility </li><ul><li>Look for the Hidden Agenda
Trust No One
Lies, Damned Lies, and Statistics </li></ul></ul>
Let's just face it:
Why do we lie? <ul><li>Charts, infographics,... are only a simplified representation of a complex reality
Compare with maps: they are also (white) lies
Used to convice others
Because it looks cool
Because we don't know any better </li></ul>
The axis are (not) your allies <ul><li>Y axis starts at 500. Why 500?
Gradients
Grey on grey
Original chart has animation... </li></ul>
Why? <ul><li>December = 1/5 size of January =  CRISIS!!!
Fear, Uncertainty and Doubt
Convince employees of needed budget cuts
Or... just blind faith in Excel??? </li></ul>
What really happened <ul><li>2008 up to Q3 was an exceptionally good year
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Common Mistakes In Data Visualization

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  • Interestingness: relevant, meaningfull, new Function: easiness, usefulness, useability, fit Form: beatty, structure, appearance Integrity: truth, consistency, honesty, accuracy Interesting + function = experiment Function + form = sketch Form + integrity = eye-candy Integrity + interesting = proof of concept Not interesting = boring Not functional = useless No form = ugly No integrity = rubbish
  • Common Mistakes In Data Visualization

    1. 1. Common mistakes in data visualization Amedee Van Gasse BarCampGhent3 19 December, 2009
    2. 2. $ whoami <ul><li>Current day job:
    3. 3. MS Office/VBA specialist
    4. 4. Desktop & Mail Security (Antivirus, Spam,...)
    5. 5. Geek stuff:
    6. 6. Ubuntu tweaking
    7. 7. Drupal ( http://foutparkeerders.be - with @peterdedecker )
    8. 8. Tik vzw ( http://tik.be )
    9. 9. [email_address] http://amedee.be http://twitter.com/amedee http://be.linkedin.com/in/amedee http://facebook.com/amedee.vangasse </li></ul>
    10. 10. The power of data visualization <ul><li>Chinese proverb: One Picture is Worth Ten Thousand Words
    11. 11. The Fast-Food Information Age
    12. 12. Pr0n for the stats junk </li><ul><li>Pointy-Haired Boss
    13. 13. Twitter: Infograph of the day ( @bnox ) </li></ul></ul>
    14. 14. What Makes Good Information Design? <ul><li>Interestingness
    15. 15. Function
    16. 16. Form
    17. 17. Integrity </li></ul>
    18. 18. With Great Power... <ul><li>... Comes Great Responsibility </li><ul><li>Look for the Hidden Agenda
    19. 19. Trust No One
    20. 20. Lies, Damned Lies, and Statistics </li></ul></ul>
    21. 21. Let's just face it:
    22. 22. Why do we lie? <ul><li>Charts, infographics,... are only a simplified representation of a complex reality
    23. 23. Compare with maps: they are also (white) lies
    24. 24. Used to convice others
    25. 25. Because it looks cool
    26. 26. Because we don't know any better </li></ul>
    27. 27. The axis are (not) your allies <ul><li>Y axis starts at 500. Why 500?
    28. 28. Gradients
    29. 29. Grey on grey
    30. 30. Original chart has animation... </li></ul>
    31. 31. Why? <ul><li>December = 1/5 size of January = CRISIS!!!
    32. 32. Fear, Uncertainty and Doubt
    33. 33. Convince employees of needed budget cuts
    34. 34. Or... just blind faith in Excel??? </li></ul>
    35. 35. What really happened <ul><li>2008 up to Q3 was an exceptionally good year
    36. 36. Yes, there was a crisis, but...
    37. 37. We went to 1/2, not to 1/5
    38. 38. Excel bug: lowest value on Y-axis is ”magic”... </li></ul>
    39. 39. What we saw in the meeting 47.988 47.115 47.385 2008 OB 2009 <ul><li>No scale
    40. 40. Why start at 40.000? Why not 30.000 or 45.000?
    41. 41. 3D adds no value </li></ul>versus 2008: - 1,3 % versus OB : + 0,6 %
    42. 42. A more accurate version <ul><li>Scale added
    43. 43. Starts at 0
    44. 44. No 3D </li></ul>versus 2008: - 1,3 % versus OB : + 0,6 %
    45. 45. You need X-Ray Vision for this one <ul><li>Confession: I made this one
    46. 46. What if executed > planned? -> invisible!
    47. 47. Better chart: bars (executed) + lines (planned) </li></ul>
    48. 48. Pie chart hell <ul><li>I made these too!
    49. 49. 3D
    50. 50. Gradients
    51. 51. Could have been combined with previous chart </li></ul>
    52. 52. Combining the two previous charts
    53. 53. The donut: evil twin of the pie <ul><li>Psychedelic
    54. 54. Hard to compare series </li></ul>
    55. 55. Can't get enough pie? <ul><li>Only one thing is worse than one pie: two pies
    56. 56. Little information
    57. 57. You can tell your story with one chart </li></ul>
    58. 58. ”Pies are to scale” <ul><li>Pretty colors
    59. 59. 3D: same diameter?Perspective? </li></ul>
    60. 60. The Mother of all Pie Charts <ul><li>http://www.slideshare.net/netlash/old-media-vs-new-media
    61. 61. Sorry, @netlash , but this one really sucks
    62. 62. Why are Greece and Germany the same size?
    63. 63. Red = good or bad?
    64. 64. Lots of comments on InformationIsBeautiful.net </li></ul>
    65. 65. The original chart <ul><li>Boring
    66. 66. Ugly
    67. 67. Easy to understand </li></ul>
    68. 68. By the way, did I already tell you that I really hate pie charts?
    69. 69. The only good pie charts Pac Man Pie: @flexyflow
    70. 70. Want to see some more silly charts?
    71. 71. Spiderman loves this one! <ul><li>Radar chart
    72. 72. Hard to read
    73. 73. Needs a lot of tweaking
    74. 74. Ugly even with perfect data </li></ul>
    75. 75. 3D: Manhattan chart <ul><li>You can always go... downtown ♫ </li></ul>
    76. 76. 3D: unstacked area chart <ul><li>This one comes with X-Ray glasses
    77. 77. Can you see S3 (yellow)?
    78. 78. Use a 2D line chart! </li></ul>
    79. 79. Some practical tips <ul><li>Colors
    80. 80. Axes, legend & title
    81. 81. Logarithmic scale </li></ul>
    82. 82. Colors <ul><li>No gradients in background
    83. 83. Background contrasts with objects
    84. 84. Use color only when needed
    85. 85. Different color = difference of meaning in data
    86. 86. Soft colors + bright/dark for highlights </li></ul>
    87. 87. Colors <ul><li>Stick with a single hue
    88. 88. Non-data just visible enough
    89. 89. Avoid red+green (colorblind)
    90. 90. Leave special effects to Hollywood!!! </li></ul>
    91. 91. And the Oscar goes to...
    92. 92. Axes, legend & title <ul><li>X Axis: Category or Value?
    93. 93. Line charts or XY Scatter charts?
    94. 94. Zero-based or not?
    95. 95. Second Y axis?
    96. 96. Good title and axis labels = no legend needed
    97. 97. If your chart needs a legend, it is a bad chart </li></ul>
    98. 98. Axes gone wrong <ul><li>X axis is time + location
    99. 99. X and Y axes ar not linear
    100. 100. A (bad) joke from http://graphjam.com </li></ul>
    101. 101. Logarithmic scale <ul><li>Nonlinear stimulus-response: 10x pay raise makes you only 2x happier
    102. 102. Avoid unless you know what you are doing
    103. 103. Can't be used with 0 in data
    104. 104. Use a trick: add 0.001 </li></ul>
    105. 105. General tips <ul><li>What is your message?
    106. 106. Who is your audience?
    107. 107. Prepare your data
    108. 108. Don't have blind faith in your software </li></ul>
    109. 109. Links http://peltiertech.com/WordPress/category/chart-busters http://chandoo.org/wp/category/visualization/ http://graphjam.com/ http://www.informationisbeautiful.net/ http://www.smashingmagazine.com/2009/09/11/ 25-useful-data-visualization-and-infographics-resources/ http://www.smashingmagazine.com/2007/08/02/ Data-visualization-modern-approaches/
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