Chance News 109

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"We’ve reached that stage of the campaign. The back-to-school commercials are on the air, and the 'unskewing' of polls has begun — the quadrennial exercise in which partisans simply adjust the polls to get results more to their liking, usually with a thin sheen of math-y words to make it all sound like rigorous analysis instead of magical thinking."

--Harry Enten, in: The polls aren’t skewed: Trump really is losing badly,, 9 August 2016

Submitted by Bill Peterson

From an 1840s letter from Charles Babbage to Alfred, Lord Tennyson, about two lines in a Tennyson poem: “Every minute dies a man, / Every minute one is born.”

“I need hardly point out to you that this calculation would tend to keep the sum total of the world’s population in a state of perpetual equipoise, whereas it is a well-known fact that the said sum total is constantly on the increase. I would therefore take the liberty of suggesting that in the next edition of our excellent poem the erroneous calculation to which I refer should be corrected as follows: ‘Every moment dies a man / And one and a sixteenth is born.’ I may add that the exact figures are 1.167, but something must, of course, be conceded to the laws of metre.”

cited by James Gleick, in The Information, 2011

Submitted by Margaret Cibes

"You can slice and dice it any way you like, but this isn’t like Consumer Reports, which tests something to see if it does or doesn’t work. The interaction between a student and an institution is not the same as the interaction between a student and a refrigerator."

-- Willard Dix, quoted in: How to make sense of college rankings, New York Times, 29 October 2016


"The LSAT predicted 14 percent of the variance between the first-year grades [in a study of 981 University of Pennsylvania Law School students]. And it did a little better the second year: 15 percent. Which means that 85 percent of the time it was wrong."

--Lani Guinier, in: The Tyranny of the Meritocracy: Democratizing Higher Education in America (Beacon Press 2015), p. 19.

Submitted by Margaret Cibes

“These chemicals are largely unknown,” said David Bellinger, a professor at the Harvard University School of Public Health, whose research has attributed the loss of nearly 17 million I.Q. points among American children 5 years old and under to one class of insecticides.

Danny Hakim, "Doubts About the Promised Bounty of Genetically Modified Crops", New York Times, October 29, 2016

Submitted by Margaret Cibes at the suggestion of Jim Greenwood

Guide to bad statistics

Our nine-point guide to spotting a dodgy statistic
by David Spiegelhalter, The Guardian, 17 July 2016

Published in the wake of the Brexit debate, but obviously applicable to upcoming US presidential election, the article offers these nine strategies for twisting numbers to back a specious claim.

  • Use a real number, but change its meaning
  • Make the number look big (but not too big)
  • Casually imply causation from correlation
  • Choose your definitions carefully
  • Use total numbers rather than proportions (or whichever way suits your argument)
  • Don’t provide any relevant context
  • Exaggerate the importance of a possibly illusory change
  • Prematurely announce the success of a policy initiative using unofficial selected data
  • If all else fails, just make the numbers up

To be continued...

Submitted by Bill Peterson

Item 2