covid-19

31 posts
Hanging things on your charts

The Financial Times published the following chart that shows the rollout of vaccines in the U.K. (I can't find the online link to the article. The article is titled "AstraZeneca and Oxford face setbacks and success as battle enters next phase", May 29/30 2021.) This chart form is known as a "streamgraph", and it is a stacked area chart in disguise.  The same trick can be applied to a column...

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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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Plotting the signal or the noise

Antonio alerted me to the following graphic that appeared in the Economist. This is a playful (?) attempt to draw attention to racism in the game of football (soccer). The analyst proposed that non-white players have played better in stadiums without fans due to Covid19 in 2020 because they have not been distracted by racist abuse from fans, using Italy's Serie A as the case study. The chart struggles to...

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Probabilities and proportions: which one is the chart showing

The New York Times showed this chart (link): My first read: oh my gosh, 40-50% of the unvaccinated Americans are living their normal lives - dining at restaurants, assembling with more than 10 people, going to religious gatherings. After reading the text around this chart, I realize I have misinterpreted it. The chart should be read by columns. Each column is a "pie chart". For example, the first column shows...

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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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Vaccine researchers discard the start-at-zero rule

I struggled to decide on which blog to put this post. The reality is it bridges the graphical and analytical sides of me. But I ultimately placed it on the dataviz blog because that's where today's story starts. Data visualization has few set-in-stone rules. If pressed for one, I'd likely cite the "start-at-zero" rule, which has featured regularly on Junk Charts (here, here, and here, for example). This rule only...

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Same data + same chart form  = same story. Maybe.

We love charts that tell stories. Some people believe that if they situate the data in the right chart form, the stories reveal themselves. Some people believe for a given dataset, there exists a best chart form that brings out the story. An implication of these beliefs is that the story is immutable, given the dataset and the chart form. If you use the Trifecta Checkup, you already know I...

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Making graphics last over time

Yesterday, I analyzed the data visualization by the White House showing the progress of U.S. Covid-19 vaccinations. Here is the chart. John who tweeted this at me, saying "please get a better data viz". I'm happy to work with them or the CDC on better dataviz. Here's an example of what I do. Obviously, I'm using made-up data here and this is a sketch. I want to design a chart...

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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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Illustrating differential growth rates

Reader Mirko was concerned about a video published in Germany that shows why the new coronavirus variant is dangerous. He helpfully provided a summary of the transcript: The South African and the British mutations of the SARS-COV-2 virus are spreading faster than the original virus. On average, one infected person infects more people than before. Researchers believe the new variant is 50 to 70 % more transmissible. Here are two...

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