We are seeing daily reports on the coronavirus outbreak situation. Organizations published charts and graphs to communicate the status. Today, I would like to share a few charts that I have come across and let’s take a look at how well they convey the information.
The first one is published by the World Health Organization. It is a map that shows the seriousness of the outbreak by country. There is a label for each country and a red circle is used to show the number of confirmed cases. The bigger the circle, the higher the number of cases. To the right, there is scale that shows what the size of the circle means. To the left, there is an inset for European countries. There is a lot of information. I found it a little cluttered and it is difficult to compare the relative sizes of the circles.
Google also uses a map to illustrate similar information. This is what the map looks like.
Instead of using circle size, it chose to use colours. The darker the blue colour, the higher the number of cases. If I want more details, the table below shows the actual count: the number of confirmed cases, no. of cases per 1M population in that country, the number of people recovered and the no. of deaths.
In comparing the two maps, I prefer the one published by Google for 2 reasons. First, the map is less cluttered and it serves the purpose in illustrating which countries have been hit the hardest. Second, details are available in a separate table for those who want to see the specific count. The one from the WHO attempts to present too much information.
The next chart shows some interesting information on how quickly the virus is spreading by country. There are 3 pieces of information provided by the European Center for Disease Control and Prevention (as of March 22, 2020.)
They are how long it took to double the total number of confirmed cases, the count of total confirmed cases at the end of each day for the past two weeks, and the count of new confirmed cases for each day.
Let’s look at how well the information is presented.
For countries where the cases doubled within a short few days, it sends a very strong message that measures need to be put in place right away to manage the spread.
The 41 days for China vs the 6 days for Italy could be misleading though. What’s hidden and not shown is that the two countries are at different stages. Italy is waking up to the outbreak while China, most parts of China, have been under lockdown for over two months.
For the two bar charts that provide information on the daily total confirmed cases and the incremental increase from day to day, visually, the increasing bar heights is excellent in illustrating how quickly the infection is spreading. In comparing the increases, US and Germany are two countries where the no. of cases are accelerating, so it is very critical that local authorities take action immediately.
The overall presentation is quite good. Could we make it simpler? One suggestion I have is to combine two bar charts, of just show one or the other but incorporate a number to show the latest count for that day.
In presenting data, there are many options. The key is to choose a format that is simplest and most straightforward for the reader to consume the information.