Comments on: ShareThis Usage Chart

By: Peter Walker

Peter Walker — Wed, 12 Nov 2008 18:01:18 +0000

Well, with 256 colors in the pallete, having enough colors isn’t a problem. Communicating clearly is the goal, and IMO a pie chart is best with 3 of fewer sections and no more than 6 (and only when to appease the sales/marketing folks who love their pie!)

By: Tony

Tony — Wed, 12 Nov 2008 17:46:53 +0000

@Peter – So I guess if you are deciding on which chart to use and a pie chart doesn’t have enough colors to uniquely identify all of the slices, there’s your sign.

I too second Jon’s comment – EXACTLY! I love being able to highlight one segment by using a distinct color compared to all of the rest.

By: Jon Peltier

Jon Peltier — Wed, 12 Nov 2008 16:05:09 +0000

Peter -

“In fact, since a bar chart works well in monochrome, it allows a second color/gradient to effectively highlight an item in the set.”

Exactly!

By: Peter

Peter — Wed, 12 Nov 2008 14:30:04 +0000

Tony – Yes. The colors repeating is an obvious problem. The repeating colors doesn’t avoid the tendency to group items that share a color. Using different saturations doesn’t get around this.

On the other hand, it was a valiant attempt to avoid the mess of applying a different color to each slide. Pie charts require differing colors/hues b/c of the direct adjacency of the slices. Bottom line, a pie chart was a bad choice.

As Jon notes, a bar chart avoids this issue. In fact, since a bar chart works well in monochrome, it allows a second color/gradient to effectively highlight an item in the set.

Good post. A clear example of the deficiency of pie charts.

By: Jon Peltier

Jon Peltier — Wed, 12 Nov 2008 11:59:06 +0000

Tony -

I think the gradients within each slice of the pie affect its apparent size, and probably color itself (intensity or ?) and orientation are factors as well.

A bar chart can avoid all of these problems.

By: Tony

Tony — Wed, 12 Nov 2008 01:59:43 +0000

Peter – I totally agree. The education slice appears to be larger than the other two. Same thing with Travel and Weather, which are both 5% but don’t look the same.

Either it’s an illusion or there is something wrong in the design. Regardless, this is precisely why pie charts with a lot of slices are ineffective.

Nobody else commented on the slices that use the same color… another sign of a poor design.

That is a very good example at the site you listed, which I have seen before and everyone should check out.

Thanks for the comment Peter!

By: Peter

Peter — Sun, 09 Nov 2008 23:03:11 +0000

My first memory of fractions in school were those little wooden blocks that we grouped together in … bars!

That was in the first grade, (Lake Heights Elem., in Bellevue, WA.) Pie charts came later as we focused on 1/2, 1/3, and 1/4 sections. But bars stayed in my classrooms through high school. I wonder if MS Excel made pie charts more ubiquitous?

The example above clearing show the problem with pie charts. Look at the three sections labeled “Education”, “Food”, and “Fashion”. All equal 3% but cleary have different widths along the arc.

I agree with David. A bar chart would likely display those difference better, as Few demonstrates, http://www.perceptualedge.com/example12.php

By: Tony

Tony — Sat, 08 Nov 2008 21:22:44 +0000

I think part of the problem is that pies are just so ingrained since early development in school. I bet the first introduction to fractions probably had to do with a pie chart. I would agree that most folks just probably don’t know any better and have never taken an interest or learned if there are better ways to present the data.

It’s good timing that you suggest Stephen’s example page at Perceptual Edge. I have an upcoming post this week with this very reference. Stay tuned.

Thanks for the comment David.

By: David Gerbino

David Gerbino — Sat, 08 Nov 2008 20:55:32 +0000

Tony,

Whenever I am forced to read pie charts I always get annoyed because a simple text table is always better. I just do not understand why the first chart type is not a horizontal bar chart. Then I am reminded that most people do not bother to learn about charting 101. I wonder how many people could learn from bad examples like those found at:

http://www.perceptualedge.com/examples.php

@dmgerbino