Here is the big hairy question of the week. What is your opinion on Pie Charts?
Pie charts are one of the most used charts in the world. And for obvious reasons: they are simple to create and easy to understand.
When it comes to pie chart, I have no clear opinion. Part of me says use them, the other says avoid them. The debate about pie charts is not just internal. Last time when Seth Godin included pie charts in his 3 laws of great presentation,
The problem with bar charts is that they should either be line/area charts (when graphing a change over time, like unemployment rates) or they should be a simple pie chart (when comparing two or three items at the same scale).
there was so much furor in the data visualization blogosphere that Seth even did a follow up post comparing bars with pie charts, where he says,
The pie chart contains far less data, but the point is obvious: Trolls are where we should focus our energy.
That’s why you use it. …
I stepped on the toes of many data presentation purists yesterday, so let me reiterate my point to make it crystal clear: In a presentation … the purpose of a chart or graph is to make one point, vividly. Tell a story and move on.
Personally I think pie charts provide great utility at very little cost:
- They are very easy to create
- Very very easy to understand (provided the data has some contrast, if your numbers are like 43,44,45,46, there is little chance that anyone can understand the resulting pie chart and make out which one is large and which one is small)
But, I also think they are easy to abuse (one reason why you see way too many pie charts compared to other charts).
Here is what I think cripples a pie chart from being effective:
- Too many data points. A pie chart would probably be effective up to 4 values, anything more and you better have a strong story behind it for people to read and interpret. For eg. the pie chart shown to the right is used in Google Analytics reports. This compares browsers used by visitors of a site and even though there are probably hundreds of browsers, only 2 are prominent, so the pie still works.
Poor use of color. The purpose of color in most visualizations is to bring contrast. To separate apples from oranges. To throw light where your story lies. But most programs that are used to generate pie charts have poor (and often scary) color choices. When you use poor color combinations, the result will be drastic. But this blame is not on the person making pie charts, but on the pie chart software. See the example aside from clearlyandsimply to see what contrast means.- Making Pie charts that are difficult to compare. The purpose of pie charts is to provide comparison. So when we make a pie chart that has poor ability to compare, we are already lost. That means we should avoid all the flashy formatting, 3d pie charts, 3d donuts and layered donuts etc. Also, whenever possible, try Using data labels, using color and if nothing works, try using other types of charts for comparison. After all, we are not selling pie charts, we are selling our stories.
Ok, now the ball is in your court (or the pie is in your plate).
What do you think about pie charts?
Do you prefer them or do you consciously avoid them ?
How do you think pie charts can be put to better and greater use ?
Your turn…
Earlier on pie charts: Why no one likes your pie & what to do about it? | In cell pie charts | 22 beautiful pie chart templates for excel
14 Responses to “Group Smaller Slices in Pie Charts to Improve Readability”
I think the virtue of pie charts is precisely that they are difficult to decode. In many contexts, you have to release information but you don't want the relationship between values to jump at your reader. That's when pie charts are most useful.
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Chandoo,
millions of ants cannot be mistaken.....There should be a reason why everybody continues using Pie charts, despite what gurus like you or Jon and others say.
one reason could be because we are just used to, so that's what we need to change, the "comfort zone"...
i absolutely agree, since I've been "converted", I just find out that bar charts are clearer, and nicer to the view...
Regards,
Martin
[...] says we can Group Smaller Slices in Pie Charts to Improve Readability. Such a pie has too many labels to fit into a tight space, so you need ro move the labels around [...]
Chandoo -
You ask "Can I use an alternative to pie chart?"
I answer in You Say “Pie”, I Say “Bar”.
This visualization was created because it was easy to print before computers. In this day and age, it should not exist.
I think the 100% Bar Chart is just as useless/unreadable as Pies - we should rename them something like Mama's Strudel Charts - how big a slice would you like, Dear?
My money's with Jon on this topic.
The primary function of any pie chart with more than 2 or 3 data points is to obfuscate. But maybe that is the main purpose, as @Jerome suggests...
@Jerome.. Good point. Also sometimes, there is just no relationship at all.
@Martin... Organized religion is finding it tough to get converts even after 2000+ years of struggle. Jon, Stephen, countless others (and me) are a small army, it would take atleast 5000 more years before pie charts vanish... patience and good to have you here 🙂
@Jon .. very well done sir, very well done.
good points every one...
I've got to throw my vote into Jon's camp (which is also Stephen Few's camp) -- bars just tend to work better. One observation about when we say "what people are used to." There are two distinct groups here (depending on the situation, a person can fall in either one): the person who *creates* the chart and the person who *consumes* the chart. Granted, the consumers are "used to" pie charts. But, it's not like a bar chart is something they would struggle to understand or that would require explanation (like sparklines and bullet graphs). Chart consumers are "used to" consuming whatever is put in front of them. Chart creators, on the other hand, may be "used to" creating pie charts, but that isn't an excuse for them to continue to do so -- many people are used to driving without a seatbelt, leaving lights on in their house needlessly, and forwarding not-all-that-funny anecdotes via email. That doesn't mean the practice shouldn't be discouraged!
[...] example that Chandoo used recently is counting uses of words. Clearly, there are other meanings of “bar” (take bar mitzvah or bar none, for [...]
[…] Grouping smaller slices in pie chart […]
Good article. Is it possible to do that with line charts?
Hi,
Is this available in excel 2013?