Mid-week entertainment: creme fraiche

From Forsooth! on RSS News, June 2007

Comments

[derek]

I don't mind this: it's just a table, really. We wouldn't grumble at a rectangular table because the boxes weren't sized in proportion to the values in the boxes, like a stacked bar chart, or because the contents of the boxes had different units and therefore weren't appropriate for adding.

[Hadley Wickham]

My memory of exactly what these labels look like is a bit dim, but I think it loses substantially when printed in black and white.

It's not a pie chart - the pieces have equal angle and are coloured green, orange, red according to the "healthiness" of that characteristic. Focussing on the colours (rather than the individual components) creates a glyph that at a glance gives how healthy the product is.

[Thomas Williams]

An actual pie chart would be grossly inappropriate here - calories couldn't be included, and protein, carbohydrate, fibre etc. would have to be. That would result in salt, and probably sugar and fat in most products, seeming almost insignificant to people who didn't know much about nutrition.

[Andy]

To Derek's point, this loses a lot without the colors. Sainsbury's calls this the Wheel of Health, and it's color coded to indicate low, medium and high levels of the key "baddies." Their thresholds between the colors are unclear, as the food type is also considered; a croissant with 188 calories is red for calories but a prepared meal with 188 calories would be green. Hmmm.... 188 calories is 188 calories, as far as I'm concerned.

[Jon Peltier]

This is a table pretending to be a pie chart. The pseudo pie chart appearance must confuse or at least distract many viewers. Color coding by "good", "medium", and "bad" is fine, but not in this pseudo chart, because it adds to the illusion that it's truly a chart.

Instead this should simply be a table in tabular form, and the rows of the table could be color coded. The five (or whatever) important items can be listed in a color-coded part at the top of the nutrition label, and the full nutritional summary could be tabulated below.

But please, no masquerading as a chart that purportedly provides information based on the size of the wedges.

[derek]

Images:
sainsburys "wheel of health"
food standards agency "traffic light"

Articles:
BBC Label wars: GDA vs traffic lights
BBC Tesco labels 'confusing shoppers'
Food Standards Agency Traffic light labelling visuals
The Food Commission Nutrition labels are designed to confuse

[Doug]

When I first saw the "chart" I laughed out loud at how ridiculous it is. I was completely in agreement with Jon Peltier's comments.

But after reading the other comments and the Wheel of Health page at Sainsbury's, I have to wonder: Do we have to sacrifice all artistic embellishment in the name of charting purity?

The circle is supposed to remind the viewer of a traffic light, and seeing it in color does help (since I'm not colorblind). If the whole thing is red: stop! Don't eat! But you can't make the whole thing red just because of one bad ingredient; some people are watching calories, others sodium, etc. So they chopped it up into slices to make a traffic light that is mostly green, say, or partially yellow. It does make a kind of sense.

Do we always need to present tabular data in rectangles? Or are pie slices just too closely associated with pie charts to be used for any other purpose?

I'm conflicted. Here's pie chart of my feelings on the matter:

80% opposed (<) 20% okay with it

[Kaiser]

Perhaps we get this reaction because pie charts are so ubiquitous, thus when we look at one, we have certain expectations. And distortion is the difference between reality and expectation.

[edmDusty]

I first look towards convention to determine the elements I use in a chart. When using graphical elements to represent data it’s easier for the reader to decode the information if he is familiar with the system used to encode it. I don’t like pie charts, but I still use them because the instant a reader looks at one he knows that the slices represent parts of a whole and he does not have to use mental resources to decode the chart. This principle works the other way too, and that is where this faux-pie chart fails. When I read the chart I instantly thought represented a whole with approximately equal parts. It was not until I noticed that the slices of pie had different units of measurements that I realized this was not a pie chart at all, but a just a round table.

[Scott Lamb]

These could be made comparable by weighting by the % of RDA supplied by each ingredient. You might even set the baseline by something like the geometric mean of that, so that overabundant or scarce (even absent) ingredients would stand out.