Bubbles, troubles

On March 23, NYT served up a double dose of bubble trouble in the business pages. For the record:

Both these displays contain very little data and perhaps the only way to read their intention is to see them as decorated data tables, in other words, as objets d'art rather than data displays.  The cutoffs and overlaps warn us against gleaning anything from the size of these bubbles.

Reference: "Who Will Work the Farms?" and "G.M. and Auto Union Reach Deal to Cut Work Force", New York Times, March 23 2006.

Comments

[paul]

The second chart certainly confused me when I read it in the paper ... I don't understand why the first two bubbles overlap.

Overlapping bubbles, to me at least, indicate that the set of people who get $70k overlaps with the set of people who get $140k. And yet there seems to be a hard break defining who gets which payout.

Maybe I'm reading it wrong.

[Jett]

While the numbers tell you the truth, the bubbles tell you a lie.

The radius is proportional to the value, but the brain perceives primarily the area, pi*r^2, so the lie factor (ratio of apparent effect to actual effect) for the illegal immigrants is (526000^2/22141^2)/(526000/22141) = 23.7

Which is too big

[Matt]

Regarding the illegal immigrants chart, if you measure the two charts, you'll see that the area is proportional to the value, not the radius.

So, the chart does accurately portray the relationships of the two numbers.