Variance

75 posts
Tongue in cheek but a master stroke

Andrew jumped on the Benford bandwagon to do a tongue-in-cheek analysis of numbers in Hollywood movies (link). The key graphic is this: Benford's Law is frequently invoked to prove (or disprove) fraud with numbers by examining the distribution of first digits. Andrew extracted movies that contain numbers in their names - mostly but not always sequences of movies with sequels. The above histogram (gray columns) are the number of movies...

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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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Ranking data provide context but can also confuse

This dataviz from the Economist had me spending a lot of time clicking around - which means it is a success. The graphic presents four measures of wellbeing in society - life expectancy, infant mortality rate, murder rate and prison population. The primary goal is to compare nations across those metrics. The focus is on comparing how certain nations (or subgroups) rank against each other, as indicated by the relative...

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Further exploration of tessellation density

Last year, I explored using bar-density (and pie-density) charts to illustrate 80/20-type distributions, which are very common in real life (link). The key advantage of this design is that the most important units (i.e. the biggest stars/creators) are represented by larger pieces while the long tail is shown by little pieces. The skewness is encoded in the density of the tessellation. So when the following chart showed up on my...

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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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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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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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Convincing charts showing containment measures work

The disorganized nature of U.S.'s response to the coronavirus pandemic has created a sort of natural experiment that allows data journalists to explore important scientific questions, such as the impact of containment measures on cases and hospitalizations. This New York Times article represents the best of such work. The key finding of the analysis is beautifully captured by this set of scatter plots: Each dot is a state. The cases...

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Bloomberg made me digest these graphics slowly

Ask the experts to name the success metric of good data visualization, and you will receive a dozen answers. The field doesn't have an all-encompassing metric. A useful reference is Andrew Gelman and Antony Urwin (2012) in which they discussed the tradeoff between beautiful and informative, which derives from the familiar tension between art and science. For a while now, I've been intrigued by metrics that measure "effort". Some years...

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Election visuals 2: informative and playful

In yesterday's post, I reviewed one section of 538's visualization of its election forecasting model, specifically, the post focuses on the probability plot visualization. The visualization, technically called  a pdf, is a mainstay of statistical graphics. While every one of 40,000 scenarios shows up on this chart, it doesn't offer a direct answer to our topline question. What is Nate's call at this point in time? Elsewhere in their post,...

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