Crosstabs and pie charts each have their own strengths when it comes to presenting visual analytics. As a previous post explained, crosstabs are best for showcasing specific information for large amounts of data, while pie charts are ideal for making comparisons within a single category.
A third type of visual analytic tool can be useful for combining the simplicity of the pie chart with the specific details found using crosstab software. This tool is known as the donut chart.
Donut charts appear similar to pie charts, with the most obvious difference being a hole in the center of the chart. Another difference is the amount of information that can be included. Different versions of donut charts can present different levels of information, starting with the most basic and ranging to a more intricate, multi-layered chart.
Basic Donut Chart
The basic donut chart is essentially a slightly amped-up version of the basic pie chart. You still only showcase one layer of information, such as the sales amounts of different sales regions. The main difference you’ll note is the ability to include the grand total in the center hole of the donut, a feature the basic pie chart typically lacks.
Donut Chart with Two Sets of Data
While the basic donut chart sticks to one layer of data, you can create a more advanced donut chart that showcases two different layers of data. This would be helpful, for instance, if you wanted to present a year-over-year comparison of regional sales.
The inner layer of data in the donut chart could feature sales for 2014, while the outer layer could present sales for 2015. Once sales figure came in for 2016, you could add a third layer of data to the donut chart if desired.
Donut Chart with More than Two Layers of Data
Each layer of data you add to the donut chart brings it closer and closer to the amount of data you can include in a crosstab, although you don’t want your donut chart to become too cluttered and overwhelming. By their very nature, donut charts are designed to provide straightforward, high-impact comparisons, and there’s a fine line between high impact and high confusion.
The donut chart below showcases four layers of data, with each ring representing a different regional sales area. As the legend points out, each different color within each ring represents a different product category. Although it is possible to include all this data in a donut chart, you’d have to ensure the chart is easy to read and makes sense at a glance.
Although it may be possible to use a donut chart to include the same level of information contained in a crosstab, the results may not always be pretty or, even more importantly, easy to follow. Crosstabs remain your best bet for featuring specific details and multiple variables in a single, comprehensive format.