When to use Bar charts vs Pie charts

An interesting post from Revlotions, an R-project and open source statistics blog, about when to use Bar charts instead of Pie charts (via Lifehacker). Visualization is not something new to the Operations Research community. Michael Trick often talks about visualization in his blog. In this blog David of Revolutions offers that point of reference is very important when visualization data.

Data is only data until it becomes information. If there is no point of reference then the data will just exist. It is when data becomes logical and leads to value is when it becomes information. Visualization is a great tool for helping to give data a point of reference. Yet using the wrong tools can lead just more obscure data that does not offer any value to its intended recipient.

(image from Revolutions)

David's post is great example of this issue within Industrial Engineering and Operations Research. It is important to frame data sets that will offer value to the intended audience. A good practioner will know the value of the data and provide it in a way that will best convey its purpose.