Junk Charts

Cram it like Koby

You have to gradually build up your gut by eating larger and larger amounts of food, and then be sure to work it all off so body fat doesn't put a squeeze on the expansion of your stomach in competition  -- Takeru Kobayashi, six-time champion of the Coney Island hot dog eating contest

Kobayashi is a phenom.  He can stuff 60 hot dogs or 100 burgers in ten or twelve minutes and show no consequences.  Ordinary people can't hope to emulate these feats.

Junk Charts sees Kobayashi as a hero; an anti-hero really.  We are ordinary people; we can't hope to cram it like Koby.  A message we keep repeating here is: too much data sinks a chart.

Not long after this chart showed up in the Economist, several readers urged us to take a look.  It's a well-nourished chart indeed, one to challenge Kobayashi, but for all that it contains, the reader has to try very hard to find insights.  What with the multiple colors, iron-fisted gridlines, above-and-below boxes, dotted and solid lines, and a legend with nine pieces split in two spots?  Besides, the U.S. boxes grab all the attention by virtue of them being wider (country being more partisan).

The key to unraveling this chart is to identify the relevant comparisons:

• UK average vs US average
• UK left vs US left
• UK right vs US right
• UK independent vs US independent

And then for the gluttonous:

• UK right vs US left
• UK left vs independent vs right
• US left vs independent vs right

In the junkchart version, we address these comparisons sequentially.

(Apologies for the tiny font.)

We are again using a small multiples approach that places four comparisons next to each other: average, left, independent, right. Consistently, the British is to the left of Americans.  The only places where the two cultures meet are where liberals agree on "ideology" and "military action".

Also note that we use a symmetric horizontal scale centered at 0.  There are too many charts out there where the center is not at the center!

A similar presentation addresses the other three comparisons.  Democrats in the U.S. are miles to the right of Tories in terms of "religion".  In the UK, Labor and Tories are not much different except on "ideology".  In the US, Independents lean closer to Democrats.

Joining the lines (I hear the grumbles) helps bring out the gap between the groups being compared.  Without lines, the chart would look like this.

It is often hard to keep track of which dot is which as they trade order from issue to issue.

PS. Anyone knows what is being measured on the horizontal axis?  The original graph mysteriously stated "respondents' views".

References: 

Eric Talmadge: "Pigout champion Kobayashi limbers up for hot dog gold" June 25, 2004

"Anglo-Saxon Attitudes", Economist, Mar 27 2008.

Little things

Reader Daniel sent us a great example of how even little things matter a lot in chart-making.  The left chart is the original.  The right chart (created by Daniel) shuffled the order of the legend to match the curves, and spaced them out.  All of a sudden, the chart is much easier to read.





Reference: "information behaviour of the researcher of the future", UCL, Jan 2008.

Clocks and pies

Keith A submitted this graphical idea from the folks at Ikea (via Boing Boing). 

Based on the comments, it seems like some people really like this presentation!

Consider these for amusement:

• Does the "9" on Sunday mean 9 am or 9 pm?  (This chart mixes A.M. and P.M. hours in a totally nonchalant way.)
• If the above is too easy, try the "9" for Saturday!
• Why was "9" displayed on Sunday anyway?  Meanwhile, why wasn't "7" displayed for Saturday?  (How were the hour labels chosen?)
• Why was "Closed" written on the chart while "High", "Mid", and "Low" were put into the legend?
• Since pie charts show proportions, is it possible to describe what proportions were plotted?

Reminds me of this pie chart.

Peripherals 1

Like any technology, charts also come with peripherals: I'm talking about legends, data labels, grid-lines and so on.  These things typically give us the most trouble, especially with complex data sets.  The analogy is apt: one may feel inextricably knotted up like bunches of cords and wires.

Interactive graphics is a particularly elegant solution to this problem, and Google Finance has done a fantastic job leading the way.  One trick is to show the legend only when the user asks for it.  Using bar charts (on the left), Google summarizes neatly the performance of stocks within each industry sector.  The bar chart gives a sense of the dispersion which adds to the average returns printed next to them.  For example, most sectors gained on average but then about 30% of the individual stocks in most sectors actually declined on that day.  So the fact that technology stocks gained 0.48% on average doesn't necessarily mean that the two tech stocks you own gained 0.48% or gained at all.

Typically, we would put a legend on the side or at the bottom of the chart, which all be told, is an ugly duckling next to a well-executed chart.  Here, the legend is hidden behind the "What's this?" link.  The side benefit is that the legend can be as verbose as needed since it doesn't interfere with the chart.

There are a few minor things to consider:

• "What's this?" is not very informative: Why not call it a "legend" or "key"?
• The graph designer seems to think that the most important information sought by readers was the extremes, i.e. the percentage of stocks that gained/lost more than 2%.  By darkening the sides of the bar, it draws attention away from the middle which is the boundary between the gainers and the losers.  I'd like to see that boundary delineated.
• Similar to the above point, I'd sketch out a version which aligns the gainer/loser boundary to the middle so it's easy to see the balance between gainers and losers.  This version however would require more space
• I'd provide sorting by average return, and by percentage of gainers

Lines of death

I've been reading my friend's anti-smoking tome, and traced this "infographic" back to its source (World Health Organization). 

I was very intrigued by the "lines of death" which seemed to make the point that the risk of death had a spatial correlation: specifically, that the death risk for male smokers was higher in northern hemisphere (above the line), primarily developed countries, as compared to the southern hemisphere, mostly developing nations.

I find that somewhat counter-intuitive but in a fascinating book like this, that brings together both scientific, psychological and societal commentary, I was expecting to learn new things.

Looking at the legend, the red areas were regions in which deaths from tobacco use accounted for over 25% of "total deaths among men and women over 35".  This explained some, as perhaps there were more reasons to die (warfare, other diseases, mine accidents, etc.) in developing nations than in developed nations, or that they had larger populations (so more deaths even at lower rates).

However, the description of the "lines of death" raised my eyebrows.  It is now claimed that more than 25% of middle-aged people (35-69 years old) die from tobacco use in the red regions. 

Did they mean 25% of the dead middle-aged people die from smoking?  Or 25% of all middle-aged folks die from smoking?  A gigantic difference!

Percentages are very tricky things to use.  Every time I see a percentage, the first thing I ask is what is the base population.  Here, the baseline appeared to have gotten lost in translation.

This set of maps also shows the peril of focusing too much on  entertainment value, and losing the plot. 

For those concerned about the effect of smoking on our society and our children, I highly recommend Dr. Rabinoff's highly readable new book, "Ending the tobacco holocaust".  It contains lots of interesting tidbits and really brings together every cogent argument that exists, including the common ones you've heard and others you haven't.

Reference: "Ending the tobacco holocaust" by Michael Rabinoff; The Tobacco Atlas by the World Health Organization

Criminal chart

The Times found a sharp surge in violent crimes.

Uh-oh. 

The legend for the columns is missing.

The maximum murder rate of about 45 per 100,000 in the top chart is depicted by a column 9x as tall as that showing the minimum rate of about 60 per 100,000 of aggravated assaults in the bottom chart.

Sorting by murder rate does disservice to the bottom chart, rendering it essentially unreadable.

Reference: "Violent Crime in Cities Shows Sharp Surge", New York Times, March 9 2007.