Sufficiency

135 posts
Pies, bars and self-sufficiency

Andy Cotgreave asked Twitter followers to pick between pie charts and bar charts: The underlying data are proportions of people who say they won't get the coronavirus vaccine. I noticed two somewhat unusual features: the use of pies to show single proportions, and the aspect ratio of the bars (taller than typical). Which version is easier to understand? To answer this question, I like to apply a self-sufficiency test. This...

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And you thought that pie chart was bad…

Vying for some of the worst charts of the year, Adobe came up with a few gems in its Digital Trends Survey. This was a tip from Nolan H. on Twitter. There are many charts that should be featured; I'll focus on this one. This is one of those survey questions that allow each respondent to select multiple responses so that adding up the percentages exceeds 100%. The survey asks...

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Circular areas offer misleading cues of their underlying data

John M. pointed me on Twitter to this chart about the progress of U.S.'s vaccination campaign: This looks like a White House production, retweeted by WHO. John is unhappy about this nested bubble format, which I'll come back to later. Let's zoom in on what matters: An even bigger problem with this chart is the Q corner in our Trifecta Checkup. What is the question they are trying to address?...

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Atypical time order and bubble labeling

This chart appeared in a Charles Schwab magazine in Summer, 2019. This bubble chart does not print any data labels. The bubbles take our attention but the designer realizes that the actual values of the volatility are not intuitive numbers. The same is true of any standard deviation numbers. If you're told SD of a data series is 3, it doesn't tell you much by itself. I first transformed this...

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Putting vaccine trials in boxes

Bloomberg Businessweek has a special edition about vaccines, and I found this chart on the print edition: The chart's got a lot of white space. Its structure is a series of simple "treemaps," one for each type of vaccine. Though simple, such a chart burns a few brain cells. Here, I've extracted the largest block, which corresponds to vaccines that work with the virus's RNA/DNA. I applied a self-sufficiency test,...

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Working with multiple dimensions, an example from Germany

An anonymous reader submitted this mirrored bar chart about violent acts by extremists in the 16 German states. At first glance, this looks like a standard design. On a second look, you might notice what the reader discovered- the chart used two different scales, one for each side. The left side (red) depicting left-wing extremism is artificially compressed relative to the right side (blue). Not sure if this reflects the...

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What is the price for objectivity

I knew I had to remake this chart. The simple message of this chart is hidden behind layers of visual complexity. What the analyst wants readers to focus on (as discerned from the text on the right) is the red line, the seven-day moving average of new hospital admissions due to Covid-19 in Texas. My eyes kept wandering away from the line. It's the sideway data labels on the columns....

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This exercise plan for your lock-down work-out is inspired by Venn

A twitter follower did not appeciate this chart from Nature showing the collection of flu-like symptoms that people reported they have to an UK tracking app.  It's a super-complicated Venn diagram. I have written about this type of chart before (see here); it appears to be somewhat popular in the medicine/biology field. A Venn diagram is not a data visualization because it doesn't plot the data. Notice that the different...

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When the visual runs away from the data

The pressure of the coronavirus news cycle has gotten the better of some graphics designers. Via Twitter, Mark B sent me the following chart: I applied the self-sufficiency test to this pie chart. That's why you can't see the data which were also printed on the chart. The idea of self-sufficiency is to test how much work the visual elements of the graphic are doing to convey its message. Look...

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The epidemic of simple comparisons

Another day, another Twitter user sent a sloppy chart featured on TV news. This CNN graphic comes from Hugo K. by way of Kevin T. And it's another opportunity to apply the self-sufficiency test. Like before, I removed the data printed on the graphic. In reading this chart, we like to know the number of U.S. reported cases of coronavirus relative to China, and Italy relative to the U.S. So,...

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