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DATA VIZ GONE WRONGWHAT NOT TO DO
Cory Jez
#DataViz15
San Jose, California
April 29, 2015
About MeOver 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
Data Viz is all around
Why Data Viz?
- Arthur Schopenhaur
Why Data Viz?
Why Data Viz?
Have you ever seen a “bad” infographic?
Source: @wtfviz
Survey
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
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
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
Redundant coloring
Redundant labeling
Background colors
Grid lines
Color legend
Low Data / Ink Ratio
Color signifies team of
interest
Remove axis, one
label for shots
No background
No grid lines
No color legend
Low Data / Ink Ratio
Remove
to
ImproveThe Data / Ink Ratio
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
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
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
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**
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**
Pie isn’t always bad….
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
How much did R.A. Dickey’s Knuckleball velocity decrease in 2013?
Source: Heap Analytics
Truncated Y-axis
How much has his velocity decreased?
How much did R.A. Dickey’s Knuckleball velocity decrease in 2013?
Source: Heap Analytics
Truncated Y-axis
6% ?
2.6% ?
Source: Heap Analytics
Remove labels & tell the story…
2.6% ?
Source: Robinhood
Remove labels & tell the story…
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
Blue or Red? Who won?
Source: wikipedia
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
Blue or Red? Who won?
Source: NY Times
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
Source: Heap Analytics
Cumulative Graphs: helpful or misleading?
Source: Heap Analytics
Cumulative Graphs: helpful or misleading?
Thanks!
cory.jez1@gmail.com
@jezlax
Linkedin.com/in/coryjez
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