
Please don't use pie charts - parallel
http://blog.jgc.org/2009/08/please-dont-use-pie-charts.html
======
btn
Edward Tufte gives the pie chart a more succinct and decisive treatment in
"The Visual Display of Quantitative Information":

    
    
      A table is nearly always better than a dumb pie chart; the
      only worse design than a pie chart is several of them, for 
      then the viewer is asked to compare quantities located in 
      spatial disarray both within and between charts [...] Given 
      their low density and failure to order numbers along a     
      visual dimension, pie charts should never be used.
    

With some additional discussion on his website:
[http://www.edwardtufte.com/bboard/q-and-a-fetch-
msg?msg_id=0...](http://www.edwardtufte.com/bboard/q-and-a-fetch-
msg?msg_id=00018S)

~~~
vannevar
Tufte is simply wrong here. A pie chart implicitly conveys an additional piece
of information which a series-style chart like a table or bar chart does not:
that the information presented represents some meaningful total. A table
listing percentages can achieve the same result, as can a single bar, but both
require closer inspection. For a small number of variables, and particularly
where there is a large disparity between the values, a pie chart is better.
Unfortunately, many people break this contract with the viewer and present a
pie chart solely to show the ratios, in which case I would agree that it is
poor presentation.

~~~
ChuckMcM
I think you may have missed his point, I had an opportunity to go to Tufte's
talk and his issue is their mixing of of area and lack of numbers. He points
out that you can take any pie chart, convert it to a stacked bar chart of one
'bar' and put the numbers along the stack axis on one side and qty labels
along the stack axis on the other side and convey more information, more
accurately, and in less space. Pie charts are big wide open wedges of color
and no additional information so they were inferior.

~~~
vannevar
What Tufte is missing is that a pie chart _does_ immediately convey one
additional piece of information that a bar chart can't without closer
inspection: that the individual wedges add up to some meaningful whole. With a
bar chart, you need some kind of explicit labeling to indicate that the bar
represents a total, whereas with a pie chart it's implicit. It's inherent from
the topology: as a circle, the pie chart is closed, implying that there is no
additional data and that only the ratios are important. A series such as a bar
chart or table is not closed, carrying the implication that it might simply
have been truncated for reasons of space or clarity. A series-style chart also
may or may not be presenting absolute values rather than ratios, and further
inspection is needed by the viewer to distinguish which is the case.

~~~
ChuckMcM
I get what you are saying, basically that the 'pie' itself is a sum of units.
However, I expect that Tufte would tell you to include that information more
succinctly (or densely). I actually re-did the graphic in Corel Draw to show
this but darned if there is a way to upload here, so I've put it in a google
'drawing' :
[https://docs.google.com/drawings/d/11hLh7DarPLrRHwVOQAC6Semn...](https://docs.google.com/drawings/d/11hLh7DarPLrRHwVOQAC6SemnARNkWEw4Bd0MPpzpj2c/edit?hl=en_US)
which may or may not come through.

The top bar, which bounds the bars with the axis label 100% conveys the same
'from a whole' concept that the pie does in less space. Its also commutive
across all three bars :-)

------
jgrahamc
Funny to see this here. There's a follow up on what to use:
[http://blog.jgc.org/2010/09/what-to-use-instead-of-pie-
chart...](http://blog.jgc.org/2010/09/what-to-use-instead-of-pie-chart.html)

------
Vivtek
Another aspect - pie charts beyond about three wedges are utterly useless to
the colorblind. The OP's Microsoft example is particularly egregious in that
aspect as well - I can't distinguish most of those colors, especially given
the minuscule legend. So the entire pie chart is quite literally wasted on me.
A blank rectangle would convey nearly as much information.

~~~
jpablo
As a colorblind myself I couldn't agree more. But this is not limited to pie
charts, any kind of graphics that uses more than 3 colors to identify labels
in a list is completely illegible for me.

~~~
eru
The smaller the coloured areas, the harder it gets for me.

So a stacked bar is mostly fine, but a scatter plot where the points are only
distinguished by colour is impossible to read.

------
ra
I think pie charts are a nice way to convey the ratio of 2 or 3 elements,
particularly when the actual numbers are unimportant.

But I agree they are sometimes used when a bar graph would be much more
appropriate.

~~~
jamesbkel
>particularly when the actual numbers are unimportant.

That's more or less my philosophy on pie charts. I find them helpful to use at
the outset of a presentation to help provide some context for what's to follow
(for example, the relative sales of Divisions A, B & C).

That said, I have no sympathy for anyone who uses side-by-side pie charts in
order to make comparisons.

------
lloeki
The (almost) only valid use of pie charts:
<http://www.27bslash6.com/p2p2.html>

~~~
latch
what about:
[http://28.media.tumblr.com/FJtUhxZXBj8kb8wlM4Qly4Ubo1_500.jp...](http://28.media.tumblr.com/FJtUhxZXBj8kb8wlM4Qly4Ubo1_500.jpg)

?

~~~
roadnottaken
pac-man pie-chart: <http://www.hemmy.net/images/games/pacmanchart.jpg>

~~~
hugh3
"This is a pie chart describing my favourite bars. And this is a bar graph
describing my favourite pies!"

<http://www.youtube.com/watch?v=f_J8QU1m0Ng>

------
buro9
And if you do use a pie chart:

* Start at 12 O'Clock

* Put the segments in sequence of size (smallest first or biggest first going clockwise)

* Add a legend or labels

* Make sure any colours you use can still be differentiated when printed greyscale

Honestly, I'd tolerate them more if I could just understand which segment was
bigger than another segment and had some meaningful way in which to vaguely
guess the value behind a segment.

~~~
TheCapn
What pie charts are good at is providing a visual comparison of a series of
values that compose a whole. Pie charts work when you're trying to represent a
_percentage_ of a total value. The example in the link about "features" is
crap because unless you're given a value of "100 features were implemented
across these versions" the comparison that Word 2000 and 2003 provided similar
values is meaningless.

Its not that you _shouldn't_ use a pie chart, it is just about knowing _when_
to use the pie chart to represent your data

------
vog
This reminds me of the PGF manual:
[http://mirror.ctan.org/graphics/pgf/base/doc/generic/pgf/pgf...](http://mirror.ctan.org/graphics/pgf/base/doc/generic/pgf/pgfmanual.pdf)

In section _7.6 Plots and Charts_ the author explains very clearly the typical
issues with bar diagrams and pie charts. Moreover, the whole chapter _7
Guidelines on Graphics_ is worth reading even for those who are not interested
in the PGF package.

The PGF manual is one of the best introductions into that topic I'm aware of.

------
raldi
Re: the claim that groups of pie charts are especially awful, I have a
counterexample. How would you express this more clearly without a series of
pie charts?

[http://en.wikipedia.org/wiki/File:Support_For_Direct_Popular...](http://en.wikipedia.org/wiki/File:Support_For_Direct_Popular_Vote.png)

~~~
jgrahamc
Like this: <http://imgur.com/rGvFW>

The example you give falls into the 'multiple pie chart' nightmare where it's
hard to compare the percentages across charts. At the same time I can easily
see how far from a majority each group is and also the pattern in abstaining
from the question.

~~~
wiredfool
But that is still not an accurate view, since the number of independents,
democrats, and republicans aren't the same.

~~~
nollidge
That doesn't mean it's inaccurate, that means it's emphasizing the comparison
between relative numbers rather than absolute numbers. If it was the way you
wanted, then the percentages would be difficult to compare.

~~~
sesqu
Not really. The chart type that incorporates that information is called a
mosaic chart, and is one of my favorites.

------
k0mplex
People would use bar charts if they had a name as delicious as a pie chart.
Perhaps we should rename them popsicle charts?

~~~
eru
How about renaming them pub charts?

------
topbanana
More pie chart hatred from a guy I used to work with.

<http://www.stevefenton.co.uk/Content/Pie-Charts-Are-Bad/>

[http://www.stevefenton.co.uk/Content/Blog/Date/201109/Blog/T...](http://www.stevefenton.co.uk/Content/Blog/Date/201109/Blog/The-
Pie-Chart-So-Bad-I-Had-To-Censor-It/)

[http://www.stevefenton.co.uk/Content/Blog/Date/201012/Blog/C...](http://www.stevefenton.co.uk/Content/Blog/Date/201012/Blog/Continued-
Pie-Chart-Hatred/)

------
porterhaney
There is a really good exception to this rule. When you're only conveying two
options in a pie chart it's much easier to discern a winner then in a table or
in a bar graph.

~~~
jimmyjay
Agreed, a bar chart with two items that have a very similar score are very
hard to read.

~~~
eru
How about just giving the two numbers?

------
paperwork
Stephen Few has pretty good books on the topic:
<http://www.perceptualedge.com/>

He is very good at explaining Tufte's work. The best part of his books and
website are comparisons between a typical charts or dashboards and his re-
designs.

Following is more relevant, his article on pie charts (PDF):
<http://www.perceptualedge.com/articles/08-21-07.pdf>

------
giberson
People like pie charts.

How do I know? Because they ask for them.

You're analysis for why pie charts are inferior at conveying information
compared to other forms of data presentation are thus moot.

~~~
klbarry
This fellow has been heavily downvoted (at 1:32 EST, anyway), but he has a
point. For conveying information, pie charts are definitely not the best. To
make an audience happy with your presentation, sometimes it is just best to
give them the pies they want. Most laymen are used to them and find them
friendlier than more complex charts.

~~~
giberson
For what it is worth, couple of things I regret about that post. I was terse,
and the tone comes off arrogant. Mainly, my use of "You're" instead of "Your"
which I'm usually careful not to mistake.

I'd like to think those are the source of the down votes--as I'd hate to
believe we've forgotten the golden rule "customer is king". If their client
comes to them and says "I want a pie chart" they should not give them 48
reasons why pie charts are terrible. They should just give them a pie chart.

I'm not suggesting that when ever they have data to convey their first thought
should be to use a pie chart. I'm simply reminding them pie charts are a
commonality of customer data visualization requests--hate them all they want
they still will be using them.

------
rgrieselhuber
We joke at Ginza that there is a direct correlation between the usage of pie
charts and software revenue.

------
Mavrik
So he took a single case where pie chart has been used wrongly and from that
extrapolated we shouldn't be using pie charts?

Seriously... either explain your logic with supports or don't bother writing
such misleading pieces of text.

~~~
cubicle67
ftfa:

\- they fail to convey information because people have a really hard time
judging relative areas instead of lengths.

\- there _are_ times when a pie chart is appropriate

\- once you get data that isn't widely different or you have lots of
categories your pie chart would be better as either a bar chart, or as simply
a data table

\- pic of horrid "word features" chart

\- why is it bad?

\- releases occur chronologically, but the data is displayed in a clockwise
fashion with no obvious starting point

\- the pie chart has no values on it at all, so we are left staring at the
chart trying to guess the relative sizes of the slices

\- the chart is 3D

\- which makes it extra bad for estimating relative sizes

\- 3D pie charts are simply an abomination

\- making them 3D just makes them even harder to interpret

------
dasil003
I was going to leave a smartass comment about the deliciousness of pie when I
scrolled down and realized that I left a similar smartass comment on the post
last time I saw it years ago.

------
ImprovedSilence
I don't know what your talking about, pie charts provide plenty of useful
information. source: <http://graphjam.memebase.com/>

------
pointyhat
Pie charts are fine if you use them carefully. Funnel charts are a sin though:

<http://peltiertech.com/WordPress/bad-graphics-funnel-chart/>

~~~
astrodust
Pie charts are never fine. They're always useless chartjunk which serve little
to no purpose. They're used all the time by people who should know better.

Even a case of comparing A vs B is better represented by bars than pie slices.

~~~
pointyhat
Bars are horrid for working out "what portion of a whole" is represented. I
don't care what iTunes does - it looks like shit.

~~~
seabee
Pies give you an at-a-glance indication of whether something is more or less
than a half (obtuse/reflex angle) or a quarter (right angle). This seems to be
the sum total of their utility.

Stacked bars may be ugly but at least you can use the segments to make more
precise measurements.

------
alphadogg
In other news, people blog about other meaningless pet peeves...

Seriously, for any chart type, there are cases of misuse, even if the over-
glorified Edward Tufte says no.

