Modern design meets dataviz
Sep 19, 2022
This chart was submitted via Twitter (thanks John G.).
Perhaps the designer is inspired by this:
That's the Royal Ontario Museum, one of the beautiful landmarks in Toronto.
The chart addresses an interesting question - how much do home buyers over or under-estimate home value? That said, gathering data to answer this question is challenging. I won't delve into this issue in this post.
Let's ask where readers are looking for data on the chart. It appears that we should use the right edge of each triangle. While the left edge of the red triangle might be useful, the left edges of the other triangles definitely would not contain data.
Note that, like modern architecture, the designer is playing with edges. None of the four right edges is properly vertical - none of the lines cuts the horizontal axis at a right angle. So the data actually reside in the imaginary vertical lines from the apexes to the horizontal baseline.
Where is the horizontal baseline? It's not where it is drawn either. The last number in the series is a negative number and so the real baseline is in the middle of the plot area, where the 0% value is.
The following chart shows (left side) the misleading signals sent to readers and (right side) the proper way to consume the data.
The degree of distortion is quite extreme. Only the fourth value is somewhat accurate, albeit by accident.
The design does not merely perturb the chart; it causes a severe adverse reaction.
P.S. [9/19/2022] Added submitter name.
This is one for the greatest hits, list. Ugh!
Posted by: art steinmetz | Sep 19, 2022 at 12:04 PM
You are too kind. There are only four data points. The colors are meaningless. The triangles are also, plus misleading. The decimals are unnecessary. The groups are different sizes. Does minus mean undervalue? Are we talking about the value of the owners' houses or their view of all houses? True chart junk.
Posted by: Richard Krablin | Sep 23, 2022 at 07:04 PM
I guess that's why they had to add the data labels, eh?
Posted by: Jon Peltier | Sep 24, 2022 at 06:18 PM