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68 posts
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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Reading an infographic about our climate crisis

Let's explore an infographic by SCMP, which draws attention to the alarming temperature recorded at Verkhoyansk in Russia on June 20, 2020. The original work was on the back page of the printed newspaper, referred to in this tweet. This view of the globe brings out the two key pieces of evidence presented in the infographic: the rise in temperature in unexpected places, and the shrinkage of the Arctic ice....

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A beautiful curve and its deadly misinterpretation

When the preliminary analyses of their Phase 3 trials came out , vaccine developers pleased their audience of scientists with the following data graphic: The above was lifted out of the FDA briefing document for the Pfizer / Biontech vaccine. Some commentators have honed in on the blue line for the vaccinated arm of the Pfizer trial. Since the vertical axis shows cumulative number of cases, it is noted that...

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Is this an example of good or bad dataviz?

This chart is giving me feelings: I first saw it on TV and then a reader submitted it. Let's apply a Trifecta Checkup to the chart. Starting at the Q corner, I can say the question it's addressing is clear and relevant. It's the relationship between Trump and McConnell's re-election. The designer's intended message comes through strongly - the chart offers evidence that McConnell owes his re-election to Trump. Visually,...

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Book Review: Visualizing with Text by Richard Barth

The creative process is sometimes described in terms of diverge-converge cycles. The diverge step involves experimentation and rewards suspending disbelief, while excesses are curbed and concepts refined during the converge step. Richard Brath's just-released book Visualizing with Text is an important resource that expands our appreciation for the place of text in visual displays. Books on data visualization fall into recognizable types, of which two popular ones are the style...

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Why you should expunge the defaults from Excel or (insert your favorite graphing program)

Yesterday, I posted the following chart in the post about Cornell's Covid-19 case rate after re-opening for in-person instruction. This is an edited version of the chart used in Peter Frazier's presentation. The original chart carries with it the burden of Excel defaults. What did I change and why? I switched away from the default color scheme, which ignores the relationships between the two lines. In particular, the key comparison...

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Election visuals: three views of FiveThirtyEight’s probabilistic forecasts

As anyone who is familiar with Nate Silver's forecasting of U.S. presidential elections knows, he runs a simulation that explores the space of possible scenarios. The polls that provide a baseline forecast make certain assumptions, such as who's a likely voter. Nate's model unshackles these assumptions from the polling data, exploring how the outcomes vary as these assumptions shift. In the most recent simulation, his computer explores 40,000 scenarios, each...

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How many details to include in a chart

This graphic by Bloomberg provides the context for understanding the severity of the Atlantic storm season. (link) At this point of the season, 2020 appears to be one of the most severe in history. I was momentarily fascinated by a feature of modern browser-based data visualization: the death of the aspect ratio. When the browser window is stretched sufficiently wide, the chart above is transformed to this look: The chart...

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On data volume, reliability, uncertainty and confidence bands

This chart from the Economist caught my eye because of the unusual use of color-coded hexagonal tiles. The basic design of the chart is easy to grasp: It relates people's "happiness" to national wealth. The thick black line shows that the average citizen of wealthier countries tends to rate their current life situation better. For readers alert to graphical details, things can get a little confusing. The horizontal "wealth" axis...

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Working with multiple dimensions, an example from Germany

An anonymous reader submitted this mirrored bar chart about violent acts by extremists in the 16 German states. At first glance, this looks like a standard design. On a second look, you might notice what the reader discovered- the chart used two different scales, one for each side. The left side (red) depicting left-wing extremism is artificially compressed relative to the right side (blue). Not sure if this reflects the...

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