Data visualization is powerful for us to explore, discover, analyze, and communicate our findings. However, when it comes to the right chart to use, some of us are at a cross road. After all, there are so many! Line chart, pie chart, bar chart, area chart, donut chart, scattered plot, the list goes on and on, and thanks to the latest data analytics technology, our choices keep growing. It becomes quite a head-scratching exercise to choose the right visualization to highlight the message in our data story. A few years ago, Dr. Andrew Abela (https://extremepresentation.com/) published a chart chooser diagram to help decide which chart is a better fit for a given data set and the perspective to communicate.
This diagram mainly focuses on 4 types of data story telling: Comparison, Distribution, Relationship, and Composition. In this post, I am going to share a few things about charts fitted for data comparison and discuss their availability on the Microsoft Power BI platform.
The “Two Variables per Item” chart on the upper right corner is a chart with different column widths; this chart is intended to communicate 2 variables at the same time, hence the different width on the x-axis. A stacked version of this is called a Marimekko/Mekko chart; it is not a common chart you see daily but for example it was used in a Bain and Company report before to highlight that China, India and Brazil dominated the other emerging market countries with respect to private equity investments. With this presentation, you can easily see the relative importance of the three key countries.
As a Power BI practitioner, I want to mention that this chart is not an available option natively but you can build it by writing R codes inside R scripts editor. The “many categories” chart right next to it, which essentially is a table with embedded charts, is also not available. Besides these 2, all the “Comparison” charts mentioned in the diagram can be easily selected in Power BI.
So.. where is the Spider-web chart to compare cyclical data? You can add it by searching for “Radar Chart” in the Power BI Visual Marketplace, click on the eclipse(…) and select “Import from marketplace” in the Visualization tool bar.
Radar Chart is sometimes referred to as a star chart; it is good for displaying multiple categories of data on each spoke of the chart. You see that chart being used a lot to convey results of someone’s personality test but it can also be used for a high level call-out of under/over-budget situation of a project by categories.
So what’s your favorite chart/visualization or the least favorite one?