time series

48 posts
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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More visuals of the economic crisis

As we move into the next phase of the dataviz bonanza arising from the coronavirus pandemic, we will see a shift from simple descriptive graphics of infections and deaths to bivariate explanatory graphics claiming (usually spurious) correlations. The FT is leading the way with this effort, and I hope all those who follow will make a note of several wise decisions they made. They source their data. Most of the...

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Bubble charts, ratios and proportionality

A recent article in the Wall Street Journal about a challenger to the dominant weedkiller, Roundup, contains a nice selection of graphics. (Dicamba is the up-and-comer.) The change in usage of three brands of weedkillers is rendered as a small-multiples of choropleth maps. This graphic displays geographical and time changes simultaneously. The staircase chart shows weeds have become resistant to Roundup over time. This is considered a weakness in the...

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Revisiting global car sales

We looked at the following chart in the previous blog. The data concern the growth rates of car sales in different regions of the world over time. Here is a different visualization of the same data. Well, it's not quite the same data. I divided the global average growth rate by four to yield an approximation of the true global average. (The reason for this is explained in the other...

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This Excel chart looks standard but gets everything wrong

The following CNBC chart (link) shows the trend of global car sales by region (or so we think). This type of chart is quite common in finance/business circles, and has the fingerprint of Excel. After examining it, I nominate it for the Hall of Shame. *** The chart has three major components vying for our attention: (1) the stacked columns, (2) the yellow line, and (3) the big red dashed...

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Graph literacy, in a sense

Ben Jones tweeted out this chart, which has an unusual feature: What's unusual is that time runs in both directions. Usually, the rule is that time runs left to right (except, of course, in right-to-left cultures). Here, the purple area chart follows that convention while the yellow area chart inverts it. On the one hand, this is quite cute. Lines meeting in the middle. Converging. I get it. On the...

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Does this chart tell the sordid tale of T1’s decline?

The Hustle has an interesting article on the demise of the T1 calculator, which is popular in business circles. The article uses this bar chart: From a Trifecta Checkup perspective, this is a Type DV chart. (See this guide to the Trifecta Checkup.) The chart addresses a nice question: is the T1 graphing calculator a victim of new technologies? The visual design is marred by the use of the calculator...

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The windy path to the Rugby World Cup

When I first saw the following chart, I wondered whether it is really that challenging for these eight teams to get into the Rugby World Cup, currently playing in Japan: Another visualization of the process conveys a similar message. Both of these are uploaded to Wikipedia. (This one hasn't been updated and still contains blank entries.) *** What are some of the key messages one would want the dataviz to...

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Tennis greats at the top of their game

The following chart of world No. 1 tennis players looks pretty but the payoff of spending time to understand it isn't high enough. The light colors against the tennis net backdrop don't work as intended. The annotation is well done, and it's always neat to tug a legend inside the text. The original is found at Tableau Public (link). The topic of the analysis appears to be the ages at...

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Choosing between individuals and aggregates

Friend/reader Thomas B. alerted me to this paper that describes some of the key chart forms used by cancer researchers. It strikes me that many of the "new" charts plot granular data at the individual level. This heatmap showing gene expressions show one column per patient: This so-called swimmer plot shows one bar per patient: This spider plot shows the progression of individual patients over time. Key events are marked...

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