Sunday, January 6, 2013

incompetent graphmaking from USA Today

USA Today' Incompetent Graph About Gun Control Poll question 'are you for or against a law which would make it illegal to manufacture, sell or possess semiautomatic guns known as assault rifles?'
click to embiggen
The green bars are calibrated to the blue 60% bar. The 44% bar is obviously incorrectly scaled.

This USA Today's poll results graph is a bit skewed. There are 2 questions shown :
1) "Which would you prefer: enforce the current gun laws more strictly and not pass new gun laws or pass new gun laws in addition to enforcing the current ones more strictly?"
2) "Are you for or against a law which would make it illegal to manufacture, sell or possess semiautomatic guns known as assault rifles?"

All of the bars are on the same scale except for one. The 44% bar showing a one point increase in support is exaggerated.   And it just coincidentally happens to enlarge the bar showing support for a ban to the same size as those who oppose it. The green bars show the roughly correct scaling.


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Their third graph used a different scale for each question. They should know that using 2 different scales make it the results less clear than they should be. They don't even mention that they are on a different scale.

USA Today using 2 different scales to on 2 bar charts side by side making the results less clear than they should be.
click to embiggen
the green bars are calibrated to the blue 62% bar on the left and the orange bars are calibrated to the blue 54% bar on the right

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