Don’t always go for the chart type you think your audience may be most familiar with. Sometimes, a more exotic chart can be more user-friendly, even to the untrained eye.
Case in point below. At the top is a Bar Chart and below it is a Dumbbell chart.
Both show the exact same data, which is the poverty rate across some OECD countries. (The poverty rate is the ratio of the number of people whose income is below the poverty line according to each country.
The winner is clear: The Dumbbell is very effective at visualizing two datasets across the same dimension in a compact and straightforward way. As a bonus, it also lets us check the spread of values (distribution) and their ranges. Finally, the Dumbbell chart is easy to create.
Many countries significantly reduce their poverty rates through redistribution of wealth (which the spread between the Before/After Taxes and Transfers values illustrate). Finland, for example, is among the top countries when it comes to reducing the poverty rate (from 34% to 6%), where South Korea, followed by the USA lag behind the other countries in reducing the poverty rate.
Compare the Dumbbell chart to the Bar chart. The latter requires twice the real estate by using two bars for each country, one bar for each data series. On top of that, the bar chart takes more effort to read and understand, since the audience has to process the values’ difference for each country by looking at both bars at the same time:
Here is another example of the power of the Dumbbell chart, where 3 variables, and their ranges from each other are visualized on one single line for each country. Despite the number of variables, the chart looks clean and easy to read. The same data set will require three bars or column for each country, that is basically 42 bars instead of just 14 using a dumbbell chart.
Even though the Dumbbell chart is a convenient chart for comparisons, as you can virtually compare an unlimited number of values on a Dumbbell chart, you have to be careful not to clutter the chart to the point where the audience gets confused. In other words, always use your common sense to create an effective chart.
Feel free to share your best Dumbbell charts, and leave a comment or a question in the comments section below.