Via Instapundit, some plotting of data from the notoriously inaccurate exit polls. That aside, the data was summarized in to graphs that seem hardly ideal for the message they’re trying to get across.
Pretty hard to read, isn’t it? It’s trying to show how much the youth support for the Republican Party dropped in this election year. But the funny construction makes it hard to read, and the axis starting at 30 makes the drop seem much more drastic than it is. The latter charge may not be strictly in violation of any rules but it certainly makes the graph initially deceptive. The data, rephrased in Google Docs (since OO.o 3’s graphs are so jaggy):
Man, look at that blue line dive! Now, I’m officially picking statistical nits with a statistics professor, but I really don’t get why he made his graphs this way. I mean, aren’t line graphs supposed to show change over time, where possible, not change over age?
Update: In comments, Hazel asks if a bar graph wouldn’t be more appropriate. Well, let’s see:
Bar graphs waste a lot of ink expressing the same information, and I’m not a general fan of them, but they do have a purpose. Where the lines in the above graph were useful for comparing the trends of one group across the years, this bar graph can show the difference in relation between groups over they years. It’s a subtle, borderline-pedantic difference, I think.
Where the first graph pretty clearly shows the decrease among the youth voters, the second graph more accurately shows the disparity between the youth vote and the rest of the vote. Both have interesting stories to tell, and, it seems to me, both present the information more clearly than the original.
Still more: A fellow Stats prof over at Columbia points out my work:
I have to say I prefer a college freshman’s plot to yours, Andrew. Although, you did hack it together at 3am after strolling around Grant Park. And drawing the y axis from 0 is a mistake which you didn’t make, too.
Ack. My sidebar did still say I was a freshman… Anyways, to this, the original author of the plots replied:
I agree–his plot is better! Age on the x-axis is good, but time is even better. I should remake my plot with all his plot’s good features plus a few improvements (fixing the y-axis, removing the horizontal lines, and labeling the lines directly rather than with a color code). Also it would be good to use NES to take the lines back to earlier years.
P.S. He also posts a bar graph, which, as he notes, is horrible.
Heh.
Posted by Hober Short 
Posted by Hober Short 
Posted by Hober Short 