Who ate all the pies?

Here at DataSalon we’re constantly looking at how best to present data in clear and intuitive ways. Top of our ‘hit list’ was to come up with a better alternative to using the humble pie chart.

Whilst they are undeniably pretty, pie charts can often be unclear and sometimes downright baffling when trying to interpret the meaning of the data behind them. For example, can you tell from the chart below which journal gets the most submissions?

The problem here is that it can be difficult to judge the difference between segments unless there are only a few of them, and their sizes are easily distinguishable. Pie charts can be effective when displaying a simple “part-to-whole” relationship (e.g. 40% male / 60% female) but don’t work so well for anything more complicated.

So, what have we done? Well, since pie charts only really become useful when you label them, this essentially makes them an alternative way of displaying a series of labels and values. So – why not just use a ranked data table instead, along with a few visual enhancements to allow for an easy way to compare relative values. The same data presented in this new way is below:

… and it now becomes clear that ‘Employee Relations’ is the most submitted journal!

For those who can’t resist a good pie, we’re still keeping those as an alternative option, at least for now.

If you’re interested in discovering more about why pie charts are not great for visualizing data, we would recommend this excellent article by Stephen Few.