When visualizing data, we often strive for efficiency: show the data, nothing else. But there can be tremendous value in redundancy to make a point and drive it home. Two recent examples from news graphics illustrate this nicely.
The first is this animated chart of global temperatures from 1881 to 2014. It shows more data than is really needed. Why show monthly data when talking about the yearly average? Why the animation of all those lines when you could just show a bar chart of the yearly averages?
But that is exactly what makes this chart work. By watching the yearly average increase, you get a much clearer (and more urgent!) sense of how temperatures are rising. The little indicator of when a new record is set doesn’t show up often at first, but then keeps going off. It’s a smart piece that takes the data and turns it into a statement.
If you haven’t seen the animated version, it’s well worth spending a minute watching. This is the difference between data analysis and communication.
The other example is a static image comparing two numbers. The numbers aren’t terribly difficult to understand or compare. They’re not even particularly big. One number is 4, the other 644. There’s clearly a difference between them, but just reading them you might not think that much of it. However, the point is driven home by actually showing the number as little icons of people.
The point this article about politicians’ health priorities becomes much more urgent through this type of information graphic than just throwing around abstract numbers. You can ignore a number you read, but you can’t ignore this visual comparison.
If anything, I think it’s a mistake to overlap the icons, which compresses them and makes it harder to appreciate the actual number. Spelling it out even more with neatly aligned, non-overlapping figures would make this point even more clearly.
Efficiency clearly has its place in visualization, in particular in analysis. But knowing when the right choice is not the efficient one is what makes all the difference when it comes to communication.