Fightin' the Good Fight... On Pies.

Pies make great weapons. Delicious, nutritious weapons. They make stupid charts. Evil, lame, boring charts. And we all know that pie charts kill kittens.

So, in the words of Nancy Reagan, "Just Say No". Unless you're in Colorado or Washington. Then just say, "Dave's not here, man". Take some time, put a little thought into it, and you can come up with a much better illustration of your data.

Step One - The Decision

A pie chart should be used to show parts in relationship to a whole. Some problems:

1. It's difficult to judge what the slices represent. As a crutch, we tend to label the slices, making a round table.
2. Designers tend to use too many slices.
3. They show part to whole without any frame of reference. (e.g. No trending)
4. They take up a lot of space and give little information.
5. Little context.

Back to the decision... What is it you are trying to say? A good place to start would be to add some trending. Think about it... one of the most common questions that we get as analysts is "are we getting better or worse?"

Step Two - The Design

Looking at the charts above, we can add one more piece of information that will help answer the 'better or worse' question. Simply give columns for current and previous month.

Step Three - The Construction

Since the last couple of tips have been fairly complicated, I've decided to make this one easy. Which is, in itself, an important tip. With a little creativity, you can make great charts with some simple expressions.

First, create a straight table and choose your dimension. The first two expressions are simple; you've done them a million times.

Next, copy the 'Current' expression and change the Representation to 'Linear Gauge'.

1. Set the Min to 0
2. Make the Mode 'Fill to Value'
3. Use only one segment.
4. Give it a non-obnoxious color
5. Hide Gauge Outlines
6. Put the following expression in the Max (using whatever set analysis is appropriate):

=Max(Aggr(Count( Distinct [Business.Key]),[Membership]))

Set the Cell Height to 2 and remove the Cell borders. You'll end up with:

Notice the lack of space between Current and the Linear Gauge. You could try to fix it by centering the Current column but it would look even worse. A better way is to simply add another expression that simply adds a blank space. Use =' ' as the expression. Then you can adjust the width of the blank column to give the appropriate white space.

Finally

That is some Chuck-Norris-level design work. Speaking of design, why would anyone write 'Juicy' across the butt of their yoga pants?