Data visualization is a way to help the viewer understands a complex or simple data by representing it in a visual context. In order to deliver the right information, it is important to know what makes it successful. First, graphs can be misleading by using the wrong scale, for example, bar graph is mostly used for comparison by representing the groups on one axis and the scale on the other axis. Moreover, the scale plays a huge role on showing the differences between the groups, according to Read Bergstrom & West's Calling Bullshit essay, bar charts should include zeros to show the true value of the group. (e.g., figure 1) it's visually noticeable that Romania's value is three times greater than France, when in fact it's only 3.8 hours.
Second, graphs are a creative tool to communicate the data with the viewer, thus it is important to take the aesthetic aspect seriously. Design elements such as colors, shapes and layout are essential tools to make a good graph, however, they can be used in a "tasteless" way. (e.g., figure 2).
As mentioned in Healy's book about What Makes Bad Figure Bad: "The bars are hard to read and compare. It needlessly duplicates labels and makes pointless use of three-dimensional effects, drop shadows, and other unnecessary design features." Not every design element can be useful in creating graphs, in the example above, the data is very simple, a flat bar graph or a pie chart would have been a better choice. The 3D projection of the chart makes it difficult for the viewer to see the gap between the bars, which makes the bar graph unsuccessful because it did not deliver the right information.
As a designer, before collecting data and sketching graphs, it is important to ask myself: What kind of impact I want to have on the viewer?
What is the most appropriate visualization that I can use to show the data?
What design elements I need to use to have a creative and legible data visualization?
I'm curious to learn other people's opinion about the aesthetic side of the process.
For example, I hate Papyrus font - used in (figure 2) - and the wooden texture bars, but my personal preferences do not define if the graph is successful or not.