Sufficiency

92 posts
Watching a valiant effort to rescue the pie chart

Today we return to the basics. In a twitter exchange with Dean E., I found the following pie chart in an Atlantic article about who's buying San Francisco real estate: The pie chart is great at one thing, showing how workers in the software industry accounted for half of the real estate purchases. (Dean and I both want to see more details of the analysis as we have many questions...

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How to describe really small chances

Reader Aleksander B. sent me to the following chart in the Daily Mail, with the note that "the usage of area/bubble chart in combination with bar alignment is not very useful." (link) One can't argue with that statement. This chart fails the self-sufficiency test: anyone reading the chart is reading the data printed on the right column, and does not gain anything from the visual elements (thus, the visual representation...

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Is the visual serving the question?

The following chart concerns California's bullet train project. Now, look at the bubble chart at the bottom. Here it is - with all the data except the first number removed: It is impossible to know how fast the four other train systems run after I removed the numbers. The only way a reader can comprehend this chart is to read the data inside the bubbles. This chart fails the "self-sufficiency...

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McKinsey thinks the data world needs more dataviz talent

Note about last week: While not blogging, I delivered four lectures on three topics over five days: one on the use of data analytics in marketing for a marketing class at Temple; two on the interplay of analytics and data visualization, at Yeshiva and a JMP Webinar; and one on how to live during the Data Revolution at NYU. This week, I'm back at blogging. McKinsey publishes a report confirming...

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Plotted performance guaranteed not to predict future performance

Kaiser Fung (Junkcharts, Principal Analytics Prep) finds a chart on French financial instruments conveys a misleading message on relative returns while failing to describe the relative risks.

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No Latin honors for graphic design

This chart appeared on a recent issue of Princeton Alumni Weekly. If you read the sister blog, you'll be aware that at most universities in the United States, every student is above average! At Princeton,  47% of the graduating class earned "Latin" honors. The median student just missed graduating with honors so the honors graduate is just above average! The 47% number is actually lower than at some other peer...

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No Latin honors for graphic design

Kaiser Fung (Junkcharts, Principal Analytics Prep) explores the big shortcoming of pictograms, that they require readers to be bean-counters. The example comes from grade inflation data in the Ivy League.

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Two views of earthquake occurrence in the Bay Area

This article has a nice description of earthquake occurrence in the San Francisco Bay Area. A few quantities are of interest: when the next quake occurs, the size of the quake, the epicenter of the quake, etc. The data graphic included in the article fails the self-sufficiency test: the only way to read this chart is to read out the entire data set - in other words, the graphical details...

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The downside of discouraging pie charts

It's no secret most dataviz experts do not like pie charts. Our disdain for pie charts causes people to look for alternatives. Sometimes, the alternative is worse. Witness: This chart comes from the Spring 2018 issue of On Investing, the magazine for Charles Schwab customers. It's not a pie chart. I'm forced to say the pie chart is preferred. The original chart fails the self-sufficiency test. Here is the 2007...

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Beauty is in the eyes of the fishes

Reader Patrick S. sent in this old gem from Germany. He said: It displays the change in numbers of visitors to public pools in the German city of Hanover. The invisible y-axis seems to be, um, nonlinear, but at least it's monotonic, in contrast to the invisible x-axis. There's a nice touch, though: The eyes of the fish are pie charts. Black: outdoor pools, white: indoor pools (as explained in...

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