Strange L-shaped trends

There is not much of a story in the expected evolution of US population, according to the United Nations estimates and projections (1950-2100): (You’ll see in a moment why there is a vertical line in 2005.) Things get a little more interesting if you split population by age groups. You can see that population is … Read more

Finally revealed: the optimal number of categories in a pie chart

It’s very simple, really: you do not compare proportions in a pie chart. Because a pie chart is not a comparison chart, it’s a part-to-whole chart. When you do this: what you really want to do is to compare each slice to the whole, like this: because, if you want to compare them you must … Read more

Bars and lines: méfiez-vous des morceaux choisis

So, this data visualization thing is new to you, but you already know enough to avoid basic mistakes (pies, 3D…). While playing with the data, you make these two charts: You already know that a bar chart helps you to compare data points, while a line chart is better at displaying trends, right? But you keep … Read more

Bamboo charts: People at risk of poverty or social exclusion

Here is the percentage of people at risk of poverty or social exclusion in the European Union and a few other countries: We are going to resist the urge to identify them and use our preconceptions against them. Let’s dig deeper instead. Some groups are more exposed to the risk of poverty. Let’s see what … Read more

The Horizon Graph Is a Reorderable Matrix Too: Unemployment Rate 1976-2012

Here is the draft result of my little weekend project, making horizon graphs in Excel: I’m probably using too many color bands, but I like it! The horizon graph is a very compact way to display lots of data points and a shiny example of how to break the rules for a good cause. It … Read more

Animation, Small Multiples or the Reorderable Matrix? Growth of Walmart, Excel Edition

In data visualization, animation is overrated. OK, it’s an interesting option if you can see a clear pattern emerging when displaying data over time/space (and, thanks to animation, we were introduced to this communicator extraordinaire named Hans Rosling). It’s fun to make an animated GIF like the one above, but you must see animation as … Read more