The sad tally 2: the data
Uh um

Polling and the obvious

I noticed a creative but flawed attempt to improve upon the stacked bar chart.  In the usual stacked bar presentation, it is easy to compare the leftmost and rightmost categories, but not the middle categories.   For example (below left), try comparing the percentage who thought women's legal rights were the same against the percentage who thought family rights were the same.

Above right, one designer's solution is to disaggregate the bars (blue, gray, red), turning them into columns of squares.  ImmigrationkeyDisaggregating the bars is a good idea but the use of squares is unfortunate, especially when the relative percentage is made proportional to the edge length, not the area of the square.  Observe that one can fit four "50%" squares into the "100%" square.

I'd welcome any ideas that would improve upon the stacked bar/column chart.  How to make the middle categories easier to compare?

The poll itself raises more questions than it answers:

  • Biased sample: Asking immigrants to compare conditions between the U.S. and other countries is like asking someone who just paid $2 million for a one-bedroom apartment in Manhattan whether there is a housing bubble.  This group made a conscious decision to come to the U.S., possibly to escape what they consider unsatisfactory circumstances in their places of birth.  It makes me wonder why we need this poll since the answers are rather obvious.
  • Heterogeneity: Immigrants come in all stripes and their answers to these questions will most likely be affected by where they came from, what socio-economic status they occupy in their home countries, what level of education they have, where they live in the U.S., their family income and so on.  The aggregate numbers do not mean much when the underlying population is so diverse.
  • It would be instructive to compare these results with polls where they ask foreigners to rate their perception of America. 

Two results were omitted from the graph for unknown reasons: 34% thought the U.S. was better on "safety from crime" and 28% thought the U.S. was better on "moral values of society".

Reference: "Migrant Worry", New York Times Magazine, Nov 6, 2005.


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With so few "Don't knows", the number of categories drops to three. In that case an alternative to the stacked bar is a ternary plot.

Here's a standard ternary plot (but I confess I always have difficulty figuring out which way the axes go).

Here's a scatterplot with the "about the same" dimension shown as contours. I think it makes your comparison ("try comparing the percentage who thought women's legal rights were the same against the percentage who thought [strength of family was] the same") possible.


I have always had mixed feelings about the ternary plot. On the one hand, I find it a brilliant invention; I still remember the first time I saw it in a geography textbook. On the other hand, it is, it seems to me, strictly for professionals.

Unless the story of the data is simple, it takes time to understand this plot. I'll find an excuse to talk more about this type of plot in the future. Thanks for bringing it up!

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