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SAS VA: Is Location just a Distracting Character in Your Dataviz?

August 24, 2015 – 2:29 pm | Comments Off on SAS VA: Is Location just a Distracting Character in Your Dataviz?

In my high school Performance Art class, our teacher, Mr. Kennedy, was constantly reminding us that when you have characters on stage the focus must remain on the central action. If you have non-speaking role then you cannot draw attention to yourself. For instance, you wouldn’t tap your foot, play with your hair or wave to the audience members.  This concept can translate into a data …

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How Not Knowing Pie Charts Makes You a #DataViz Rookie

May 7, 2015 – 10:15 am | 5 Comments

If I live to be 115 years old, I’ll never understand why consultants use pie charts. Your chance of doing them wrong is greater than doing them right. At the SAS Global Forum last week, I was delighted to hear several others telling me how much they hated pie charts and we agreed, they need to be stomped out – we are forming a #DataVizArmy to do just that.  Our first mission is to rid the world of poorly done pie charts.

Guidelines for Using Pie Charts

Here’s the guidelines for how to properly use a pie chart to display your data. I use the word guidelines because there are times (few and far between) that it makes sense not to do it this way.

Remember: Pie charts are used to show the parts to the whole.

  • Parts to a whole equals 100% – always
  • Limit to 4 or 5 categories
  • Doesn’t need a legend when done properly
  • Better when one category is significant percentage-wise
  • Not suitable for comparisons

When It Looks Good

Here’s examples of good pie charts. Notice that not having the percentage doesn’t matter that much – you know that Tracy is spending too much time trying to find the right content on Netflix and not enough time taking care of business.  (Names changed to protect the lazy.)

good pie chart

I like that the author went to the extra trouble of noting why the values may not equal 100%. Maybe having the percentage makes it seem more scientific?


Rookies Love Chart Junk

When you don’t understand the guidelines above, you are at greater risk for creating chart junk. Let’s look at some examples of when these guidelines were not followed to further convince you.

Is your data suitable for a pie chart?

Remember – the data is supposed to be the parts to a whole. What is the author’s point is with this pie chart? There’s not any numbers here – just dates and drug names. This chart only informs me that anti-coagulants were introduced in 1982 and more have entered the market since that date. It doesn’t express perhaps the different categories, the popularity, or anything really.  Use a line chart when you want to show a timeline or a simple line that shows the dates.

bad pie chart 01

Legends might make the pie chart superfluous

If you are thinking of adding a graphical element to the page, this is where you fall into the trap.  Really question yourself if you start reaching for a pie chart – that’s a rookie move.  For instance, does this chart really add anything besides some color?  I bet you just read the numbers and didn’t even notice the chart.


Famous example of Breaking the 100%

Again ask yourself does this data make sense as a pie chart? Just about anytime you read about pie charts – you are likely to see this example.  It’s hard to believe someone was so confused.  It’s back to that need to show data visually but not understanding what you are doing.  Are you glad they listed the percentage – otherwise the fault when have gone unnoticed.

bad pie charts 05

Limit the categories to focus the reader’s attention

When you have too many categories it makes it harder for the reader to understand your point. The reader may ask themselves “Is this a ranking?” or “Do these other categories really matter – why am I being shown this?”  Again notice how going back and forth between the colors and legend is a drag.  This would make more sense as horizontal bar chart.


It’s Hard to Compare Pies

Avoid using pie charts to compare to things – it’s harder on your reader.  The reader had to keep a lot of information in their visual memory – the order of the categories and the values.  So the comparison is really difficult and taxing.

pie charts hard to compare

Click for larger image

Review the difference when I rebuilt the chart in SAS Visual Analytics.  I used a butterfly chart, which is really just two bar charts back to back.  It’s a lot easier to compare the numbers and more clear how different the spending is.  Maybe you didn’t notice before that rich don’t spend a lot of their money on tobacco or perhaps it’s not a large enough percentage to register.  They do spend more on personal insurance and pensions!

Click image to see larger

Click image to see larger

More Rookie Alerts

What do you think the message is … “I don’t know what I’m doing?” or “Watch mom – I can do colors.”

bad pie charts


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Attending SESUG 2015?

If you are planning to attend SESUG 2015 in beautiful Savannah, Georgia on Sept 29 then join me for my talk about data visualization "How to be the MacGyver of Data Visualization"! I'll show you some cool ways to visualize data with SAS Visual Analytics as well as some traps to avoid.

Data Visualization is on Tap at #SASGF15

April 22, 2015 – 7:30 am | One Comment

This post first appeared on The 10 Minute SAS Coach site.  Thanks Guy Garrett for contributing to BI-Notes.
The SAS Global Forum is an event where SAS professionals from around the world meet once a year to see the latest R&D from SAS Institute, discuss current trends in Business Intelligence, Analytics and Big Data, and hear papers from colleagues on all manner of subjects ranging from Arrays …

6 Tips for Data Visualization from a Floral Designer

March 26, 2015 – 7:35 am | Comments Off on 6 Tips for Data Visualization from a Floral Designer

You never know where you will find inspiration. This past weekend I attended the NC Museum of Art Art in Bloom Festival.  The idea is that local floral designers use a museum masterpiece to draw inspiration for a floral design. [More: WRAL video about event] It was incredible to see how someone could paint with flowers. Turns out there are many Art in Bloom events like …

SAS Coding: Use Flowcharts to Learn Inherited SAS Code

March 2, 2015 – 8:00 am | 5 Comments

I’m a visual person – I always need a picture. As a consultant, many times I’m given a thumb drive full of code and asked to make modifications.  When you are on a project with me, you’ll grow weary of hearing me say “Can you draw it?” Something magical happens for me when I see a flow or see an idea.
One of the most confusing projects I …

Wanted! SAS Rustlers Unite at #SASGF15 #TweetUp

February 22, 2015 – 12:23 pm | 9 Comments

In April 2015, SAS users travel across the world to the SAS Global Forum in Dallas, Texas – yes the legendary Wild West.  If you are arriving early at the conference (maybe for a workshop or to take a certification exam) – then you’re invited to a special and exclusive event.

#SASGF15 Tweeps Unite!
This is an informal, pre-conference gathering for tweeps on Saturday 25th April at 8 PM at the conference hotel. …

Administration: What Demons Are at Your Command?

October 28, 2014 – 12:10 pm | 4 Comments
Charleston Cemetary

In the US, Halloween is celebrated by young children dressing up as ghouls, ghosts, and demons of other sorts.  I think the original idea of costumes was to be the scarier demon, which means if I look like a bad ass demon then maybe the truly bad ass demons will run away in fright. This made me wonder What do I truly find scary? Turns out it is not graveyards, …