Data Viz Gone Wrong Presentation at 2015 Data Viz Summit #DataViz15

1. DATA VIZ GONE WRONG
WHAT NOT TO DO
Cory Jez
#DataViz15
San Jose, California
April 29, 2015

2. About Me
Over 4 years working as a
BI Analyst, Consultant, and Trainer
Tableau Desktop Certified, Tableau
Certified Trainer
Winner: 2014 Tableau Viz as Art
Fantasy Football & Data Viz

3. Data Viz is all around

4. Why Data Viz?
- Arthur Schopenhaur

5. Why Data Viz?

6. Why Data Viz?

7. Have you ever seen a “bad” infographic?
Source: @wtfviz
Survey

8. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

9. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

10. ink used to print data points
Data-ink ratio =
total ink used to print graphic
Source: The Visual display of Quantitative Information, Edward Tufte
Low Data / Ink Ratio

11. Redundant coloring
Redundant labeling
Background colors
Grid lines
Color legend
Low Data / Ink Ratio

12. Color signifies team of
interest
Remove axis, one
label for shots
No background
No grid lines
No color legend
Low Data / Ink Ratio

13. Remove
to
Improve
The Data / Ink Ratio

14. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

16. A lot of data in a tight space
Color scheme used to be congruent with the flag, not to highlight data
Should data about Americans always be represented by a flag?
All metrics are presented in-line with each other (race, age, citizenship)
Male / Female splits are automatically in 2% buckets (50 stars)
Source: junkcharts.com
Data Deluge

17. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

18. Source: buzzfeed.com
Too Much Pie
Issues:
Uninformative title
Too many pies make comparisons
difficult
Sort ordering
Names in ALL CAPS
Dem and Rep labels are switched
Not all pies add up to 100%
**You just end up reading numbers**

19. Source: buzzfeed.com
Too Much Pie
Solutions:
Title is more clear
Stacked bars make comparison
easier
Ordered by positive sentiment
Labeling is aligned
Visually see some bars +/- 100%
**You can visualize the winners/losers
and the trends now**

20. Pie isn’t always bad….

21. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

22. How much did R.A. Dickey’s Knuckleball velocity decrease in 2013?
Source: Heap Analytics
Truncated Y-axis
How much has his velocity decreased?

23. How much did R.A. Dickey’s Knuckleball velocity decrease in 2013?
Source: Heap Analytics
Truncated Y-axis
6% ?

24. 2.6% ?
Source: Heap Analytics
Remove labels & tell the story…

25. 2.6% ?
Source: Robinhood
Remove labels & tell the story…

26. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

27. Blue or Red? Who won?
Source: wikipedia

28. Geo’s are not sized by population
Some of the largest places: NYC, Boston
appear very small on a map
Solutions
Use “size” to denote population density
Accompany maps with aggregate data
Interactivity – allow for zooming and filtering
Geo Maps

29. Blue or Red? Who won?
Source: NY Times

30. Unclear, difficult to understand
Low Data / Ink Ratio
Data Deluge
Too much pie
Misleading or intentionally distorting our data
Truncate Y-Axis
Geographic Data
Cumulative Graphs
Data Viz Gone Wrong

31. Source: Heap Analytics
Cumulative Graphs: helpful or
misleading?

32. Source: Heap Analytics
Cumulative Graphs: helpful or
misleading?

34. Thanks!
cory.jez1@gmail.com
@jezlax
Linkedin.com/in/coryjez