This Wimbledon beauty will be ageless

Ft_wimbledonage


This Financial Times chart paints the picture of the emerging trend in Wimbledon men’s tennis: the average age of players has been rising, and hits 30 years old for the first time ever in 2019.

The chart works brilliantly. Let's look at the design decisions that contributed to its success.

The chart contains a good amount of data and the presentation is carefully layered, with the layers nicely tied to some visual cues.

Readers are drawn immediately to the average line, which conveys the key statistical finding. The blue dot  reinforces the key message, aided by the dotted line drawn at 30 years old. The single data label that shows a number also highlights the message.

Next, readers may notice the large font that is applied to selected players. This device draws attention to the human stories behind the dry data. Knowledgable fans may recall fondly when Borg, Becker and Chang burst onto the scene as teenagers.

 

Then, readers may pick up on the ticker-tape data that display the spread of ages of Wimbledon players in any given year. There is some shading involved, not clearly explained, but we surmise that it illustrates the range of ages of most of the contestants. In a sense, the range of probable ages and the average age tell the same story. The current trend of rising ages began around 2005.

 

Finally, a key data processing decision is disclosed in chart header and sub-header. The chart only plots the players who reached the fourth round (16). Like most decisions involved in data analysis, this choice has both desirable and undesirable effects. I like it because it thins out the data. The chart would have appeared more cluttered otherwise, in a negative way.

The removal of players eliminated in the early rounds limits the conclusion that one can draw from the chart. We are tempted to generalize the finding, saying that the average men’s player has increased in age – that was what I said in the first paragraph. Thinking about that for a second, I am not so sure the general statement is valid.

The overall field might have gone younger or not grown older, even as the older players assert their presence in the tournament. (This article provides side evidence that the conjecture might be true: the author looked at the average age of players in the top 100 ATP ranking versus top 1000, and learned that the average age of the top 1000 has barely shifted while the top 100 players have definitely grown older.)

So kudos to these reporters for writing a careful headline that stays true to the analysis.

I also found this video at FT that discussed the chart.

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This chart about Wimbledon players hits the Trifecta. It has an interesting – to some, surprising – message (Q). It demonstrates thoughtful processing and analysis of the data (D). And the visual design fits well with its intended message (V). (For a comprehensive guide to the Trifecta Checkup, see here.)


Inspiration from a waterfall of pie charts: illustrating hierarchies

Reader Antonio R. forwarded a tweet about the following "waterfall of pie charts" to me:

Water-stats-pie21

Maarten Lamberts loved these charts (source: here).

I am immediately attracted to the visual thinking behind this chart. The data are presented in a hierarchy with three levels. The levels are nested in the sense that the pieces in each pie chart add up to 100%. From the first level to the second, the category of freshwater is sub-divided into three parts. From the second level to the third, the "others" subgroup under freshwater is sub-divided into five further categories.

The designer faces a twofold challenge: presenting the proportions at each level, and integrating the three levels into one graphic. The second challenge is harder to master.

The solution here is quite ingenious. A waterfall/waterdrop metaphor is used to link each layer to the one below. It visually conveys the hierarchical structure.

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There remains a little problem. There is a confusion related to the part and the whole. The link between levels should be that one part of the upper level becomes the whole of the lower level. Because of the color scheme, it appears that the part above does not account for the entirety of the pie below. For example, water in lakes is plotted on both the second and third layers while water in soil suddenly enters the diagram at the third level even though it should be part of the "drop" from the second layer.

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I started playing around with various related forms. I like the concept of linking the layers and want to retain it. Here is one graphic inspired by the waterfall pies from above:

Redo_waterfall_pies