Here again are the slides I discussed yesterday: http://newenergytimes.com/v2/library/2010/2010KrivitS-ACS.pdf
A few weeks ago, Krivit discussed here the graph shown on Slide 30. I pointed out that it should show the zero line, and it should include error bars. In the presentation Krivit put it back the way it was, and for good measure he removed the Y-axis labels.
This annoying trick is described on p. 62 of a marvelous little book by Darrell Huff, "How to Lie with Statistics" (1954, now in its 39th printing). He describes a graph showing a 10% increase in national income:
"Now that's clear enough. [The graph] shows what happened during the year and it shows a month by month. He who runs may see and understand, because the whole graph is in proportion and there is a zero line at the bottom for comparison. Your 10% looks like 10% -- an upward trend that a substantial but perhaps not overwhelming.
This is very well if all you want to do is convey information. But suppose you wish to win an argument, shock a reader, move him into action, sell him something. For that this chart lacks schmaltz. Chop off the bottom.
Now that is more like it. . . . the figures are the same and so is the curve. It is the same graph. Nothing has been falsified -- except the impression that it gives. . . ."
This book was printed the year I was born. As I recall, my mother gave me a copy as a child with the admonition: "grown-ups sometimes lie." In other words, Krivit does not know any tricks that I didn't learn at my mother's knee.
I am fond of petite women, short poems, and little books. To learn how to write, read Strunk and White, "The Elements of Style." To learn how to bamboozle people with numbers, read Huff.
- Jed
