bar chart

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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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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Distorting perception versus distorting the data

This chart appears in the latest ("last print issue") of Schwab's On Investing magazine: I know I don't like triangular charts, and in this post, I attempt to verbalize why. It's not the usual complaint of distorting the data. When the base of the triangle is fixed, and only the height is varied, then the area is proportional to the height and thus nothing is distorted. Nevertheless, my ability to...

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Did the pandemic drive mass migration?

The Wall Street Journal ran this nice compact piece about migration patterns during the pandemic in the U.S. (link to article) I'd look at the chart on the right first. It shows the greatest net flow of people out of the Northeast to the South. This sankey diagram is nicely done. The designer shows restraint in not printing the entire dataset on the chart. If a reader really cares about...

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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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Reading this chart won’t take as long as withdrawing troops from Afghanistan

Art sent me the following Economist chart, noting how hard it is to understand. I took a look, and agreed. It's an example of a visual representation that takes more time to comprehend than the underlying data. The chart presents responses to 3 questions on a survey. For each question, the choices are Approve, Disapprove, and "Neither" (just picking a word since I haven't seen the actual survey question). The...

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Two commendable student projects, showing different standards of beauty

A few weeks ago, I did a guest lecture for Ray Vella's dataviz class at NYU, and discussed a particularly hairy dataset that he assigns to students. I'm happy to see the work of the students, and there are two pieces in particular that show promise. The following dot plot by Christina Barretto shows the disparities between the richest and poorest nations increasing between 2000 and 2015. The underlying dataset...

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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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Re-engineering #onelesspie

Marco tweeted the following pie chart to me (tip from Danilo), which is perfect since today is Pi Day, and I have to do my #onelesspie duty. This started a few years ago with Xan Gregg. This chart supposedly was published in an engineering journal. I don't have a clue what the question might be that this chart is purportedly answering. Maybe the reason for picking a cellphone? The particular...

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