For this months’ #SWDChallenge the brief was simple; find a less-than-perfect chart and make it better.

It didn’t take me long to find some ideal charts for this exercise on the Internet. I settled for this one from HowMuch because the dataset was simple and easy to transpose into Excel:


What do I like about it?

  • The bubble sizes are shown in order from largest to smallest
  • Clear ‘how to read’ key
  • The data sources are clearly noted in the footnote

What could be improved?

  • The bubbles aren’t sized in perspective
  • The use of bubbles makes comparisons difficult
  • The logos make the chart look cluttered
  • The logos are used twice; once within the bubbles and once outside. This is unnecessary and adds further clutter
  • Given the title references Visa and Paypal, the chart does not explicitly show these versus the other payment methods

My approach

I wanted to keep my chart simple so opted to use a bar chart. I also wanted to highlight Visa in a different colour since they handle so many more transactions per second versus the other payment methods listed.

I considered using the payment method logos as axis labels (instead of the payment method names) using the tutorial I wrote on this method here. However, I felt this made the view look cluttered so I opted for a more traditional view.

I re-worded the title as I didn’t think it made sense to reference Paypal since they handle considerably fewer transactions per second versus Visa.

Here’s my completed viz:

Cryptocurrencies vs. Visa #SWDChallenge

(Click on the image to view the interactive version on Tableau Public)

Why it works

In this view it is much easier to compare the payment methods and determine which handle more transactions per second in comparison to the original chart. The difference between Visa and the second-fastest payment method ‘Ripple’ is much clearer in this view also. In the original chart the difference between Visa and Ripple appeared less since the bubbles were not sized correctly.

Given that some of the payment methods handle low volumes of transactions per second versus Visa they are quite difficult to see in the bar chart view. The only way to combat this would be to remove Visa altogether and perhaps use a title to make the comparison instead. However, I felt it best to include Visa so better comparisons could be drawn from the data.

Remember, the #SWDChallenge is a monthly challenge. Follow the Storytelling With Data blog for more information on how to participate.

Thanks for reading.