The document discusses using a skyline graph to compare data over time instead of pie charts. It notes that skyline graphs make it easier to see relative changes between categories and identify the biggest changes. The presentation provides examples of skyline graphs and how they better convey stories about "what happened" with data comparisons than traditional charts like pie charts.

1. Interaction12, Dublin, Ireland. 4 Feb 2012
Telling the Data Comparison
Story Using A Skyline Graph
(Instead of Two Pies)
Bill Caemmerer
bcaemmerer@sapient.com
bill@caemmerer.net

2. Just like every picture, every graph tells a story, or it
should. Frequently the story we want to tell is a
comparison to the past or to our plans, a “what
happened” story.
Do we have the best tools to tell this story visually,
in graphs? In this presentation, we'll look at the
common strategies like pies, bars, thermometers
and heat maps, and how well they tell us “what
happened.”

3. Is this any way to manage your retirement?

5. Then Now
Tamborines Tamborines
Guitars Guitars
Bodhrans
Bodhrans
Banjos Banjos
Basses
Basses
Fiddles Fiddles

6. Then Now
Tamborines
Tamborines
Guitars Guitars
Bodhrans
Bodhrans
Banjos Banjos
Basses
Basses
Fiddles
Fiddles
area= (angle/360)*π r 2

7. Tough questions (for pie charts):
• how much did any item change?
• what+do you mean by “percent”
20% 5% = 21%.. ??

8. Comparison stories: “what
happened?”

9. We want to know:
• Relative changes
(“left shoe sales are up 15%”)
• Biggest most important changes
(“you spent $500 on what?!”)

14. What makes details easy to see?

15. horizons

16. silhouettes

17. Variation from a horizon line
Height and width
Size or area

18. 160%
140%
120%
Now
100%
80%
60%
40%
20%
Then

19. 160%
area = x*y
140%
120%
Now
100%
80%
60%
40%
20%
Guitars Banjos Fiddles Basses Bodhrans Tamborines
25 14 17 10 20 14
Then

20. 160%
140%
120%
Now
100%
80%
60%
40%
20%
Guitars Banjos Fiddles Basses Bodhrans Tamborines
25 14 17 10 20 14
Then

21. 160%
140%
30
120%
Now
100%
80%
60%
40%
20%
Guitars Banjos Fiddles Basses Bodhrans Tamborines
25 14 17 10 20 14
Then

22. 28
160%
140%
30
120% 11
20
Now
100% 12
80%
9
60%
40%
20%
Guitars Banjos Fiddles Basses Bodhrans Tamborines
25 14 17 10 20 14
Then

24. Fo
o d
&
D
in
in
g
Au
to
&
Tr
a ns
po
rt
Bi
lls
&
U
til
iti
e s
Spending By Category
Bu
si
ne
ss
Se
rv
ic
es
Fi
n an
ci
al
Ed
uc
at
io
n
Sh
op
pi
U ng
nc
at
eg
or
iz
ed
G
ift H
s om
& e
D
on
at
io
ns
O
th
er

26. 20%
40%
60%
80%
120%
140%
100%
H
om
e:
M
or
t ga
ge
&
R
en
t
$525
Fo
o d
&
D
in
in
$525
g:
G
Spending vs. Budget
ro
ce
rie
Ed s
$250
uc
Spending v Budget
at
io
n:
$225
Au St
ud
to en
Au & tL
Tr
to a oa
& ns n
$250
Tr po
a rt:
ns
po G
as
$250
Bi
rt:
A &
lls ut Fu
Bi & o el
lls U In
$120
&
$169
til su
U iti ra
til es
iti :E nc
e
$102
es l
$44
: M ect
ob ric
ity
$100
En ile
te Ph
rt o
ai n
$70
$70
nm e
en
t
$50
$31

27. scales well horizontally

28. Technology
+4.3%
Industrial Goods
Conglomerates Utilities
+2.3% Consumer Goods AAPL +7.4% +0.3%
-11.0%
MSFT -7.7%
Services
Basic Materials +11.2%
GOOG +0.8%
+0.0% Financial
+8.6%
YHOO -3.2%
scales well horizontally

29. Where to find out more...

30. Search online for:
variable-width column charts
variwide charts
bar-mekko charts
coming soon: skylinechart.net

31. Thank you!
bcaemmerer@sapient.com
bill@caemmerer.net