Data

160 posts
A German obstacle course

A twitter user sent me this chart from Germany. It came with a translation: "Explanation: The chart says how many car drivers plan to purchase a new state-sponsored ticket for public transport. And of those who do, how many plan to use their car less often." Because visual language should be universal, we shouldn't be deterred by not knowing German. The structure of the data can be readily understood: we...

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What does Elon Musk do every day?

The Wall Street Journal published a fun little piece about tweets by Elon Musk (link). Here is an overview of every tweet he sent since he started using Twitter more than a decade ago. Apparently, he sent at least one tweet almost every day for the last four years. In addition, his tweets appear at all hours of the day. (Presumably, he is not the only one tweeting from his...

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The what of visualization, beyond the how

A long-time reader sent me the following chart from a Nature article, pointing out that it is rather worthless. The simple bar chart plots the number of downloads, organized by country, from the website called Sci-Hub, which I've just learned is where one can download scientific articles for free - working around the exorbitant paywalls of scientific journals. The bar chart is a good example of a Type D chart...

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The envelope of one’s data

This post is the second post in response to a blog post at StackOverflow (link) in which the author discusses the "harm" of "aggregating away the signal" in your dataset. The first post appears on my book blog earlier this week (link). One stop in their exploratory data analysis journey was the following chart: This chart plots all the raw data, all 8,760 values of electricity consumption in California in...

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Type D charts

A twitter follower sent the following chart: It's odd to place the focus on China when the U.S. line is much higher, and the growth in spending in the last few years in the U.S. is much higher than the growth rate in China. In the Trifecta Checkup, this chart is Type D (link): the data are at odds with the message of the chart. The intended message likely is...

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Visual design is hard, brought to you by NYC subway

This poster showed up in a NY subway train recently. Visual design is hard! What is the message? The intention is, of course, to say Rootine is better than others. (That's the Q corner, if you're following the Trifecta Checkup.) What is the visual telling us (V corner)? It says Rootine is yellow while Others are purple. What do these color mean? There is no legend to help decipher it....

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Check your presumptions while you’re reading this chart about Israel’s vaccination campaign

On July 30, Israel began administering third doses of mRNA vaccines to targeted groups of people. This decision was controversial since there is no science to support it. The policymakers do have educated guesses by experts based on best-available information. By science, I mean actual evidence. Since no one has previously been given three shots, there can be no data on which anyone can root such a decision. Nevertheless, the...

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What metaphors give, they take away

Aleks pointed me to the following graphic making the rounds on Twitter: It's being passed around as an example of great dataviz. The entire attraction rests on a risque metaphor. The designer is illustrating a claim that Covid-19 causes erectile dysfunction in men. That's a well-formed question so in using the Trifecta Checkup, that's a pass on the Q corner. What about the visual metaphor? I advise people to think...

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Did prices go up or down? Depends on how one looks at the data

The U.S. media have been flooded with reports of runaway inflation recently, and it's refreshing to see a nice article in the Wall Street Journal that takes a second look at the data. Because as my readers know, raw data can be incredibly deceptive. Inflation typically describes the change in price level relative to the prior year. The month-on-month change in price levels is a simple seasonal adjustment used to...

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Start at zero improves this chart but only slightly

The following chart was forwarded to me recently: It's a good illustration of why the "start at zero" rule exists for column charts. The poor Indian lady looks like a midget in this women's club. Is the average Indian woman really half as tall as the average South African woman? (Surely not!) The problem is only superficially fixed by starting the vertical axis at zero. Doing so highlights the fact...

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