Chance News 64
Quotations
We tolerate the pathologies of quantification — a dry, abstract, mechanical type of knowledge — because the results are so powerful. Numbering things allows tests, comparisons, experiments. Numbers make problems less resonant emotionally but more tractable intellectually. In science, in business and in the more reasonable sectors of government, numbers have won fair and square.
--Gary Wolf
Writing in The data-driven life, New York Times, 26 April 2010
Submitted by Bill Peterson
Forsooth
Pitching is 80% of the game. The other half is hitting and fielding.
--former Yankee Mickey Rivers
Quoted in “Is Greinke the Unluckiest Pitcher Ever?”
The Wall Street Journal, May 5, 2010
(See more great quotes online at "Mickey Rivers' Words of Wisdom About Baseball".)
Submitted by Margaret Cibes
Fixing the census
The following article was suggested by Laura Chihara on the Isolated Statisticians list:
The census will be wrong. We could fix it.
by Jordan Ellenberg, Washington Post, 1 May 2010
Odds are, it’s wrong--Part II
An entry in Chance News 63 presented a Science News article by Tom Siegfried. The article, which focuses on statistics used in the medical field, may be found here and is worth some elaboration; be sure to read the comments reacting to what Siegfried writes. There you will find mention of circumcision, condoms, defense of statistics in medicine, praise for the author, condemnation of the author--and somehow, reference to Scott Reuben, who faked data for Pfizer and Merck (see Serious medical fraud in Chance News 45).
Siegfried’s main contention is that despite its prevalence in the medical sphere (and dominance elsewhere as well), Fisher’s p-value approach is inadequate and misleading at best. Because of this “p-value mania,” Siegfried quotes two researchers who claim “that in modern [medical] research, false findings may be the majority or even the vast majority of published research claims,” and “There are more false claims made in the medical literature than anybody appreciates,” respectively.
Criticism of p-value is hardly new. Put “criticism of p-value” into a browser and you will get 4,520,000 hits, many of which are more informative than Siegfried’s article. Try The P-value, devalued from the International Journal of Epidemiology as an example.
Discussion
1. To see why critics of p-value say it is the wrong-way round, consider Prob ( brown eyes | Costa Rican) and Prob (Costa Rican | brown eyes). Compare with Prob (data | Null Hypothesis is true) and Prob (Null Hypothesis is true | data). For an interesting illustration of the difference between these conditional probabilities regarding the O.J. Simpson murder case see Steven Strogatz’s NYT article (25 April 2010).
2. Critics of p-value say that the above #1 is not strong enough of a criticism because p-value deals not with “data” that actually occurred but with “data at least this extreme.” Why is this a potent criticism?
3. Siegfried rightfully refers to “randomized, controlled clinical trials that test drugs for their ability to cure or their power to harm” as the “gold standard” for medical research. “Such trials assign patients at random to receive either the substance being tested or a placebo.” However, see Judson’s NYT article, Enhancing the Placebo (3 May 2010), which discusses how non-placebo a placebo can be. What does this do to clinical trials and the gold standard?
4. Siegfried suggests that Bayesian inference is preferable to the frequentist p-value approach of Fisher. If this is so, why is it that p-value approach is so dominant, long after Fisher himself died?
Submitted by Paul Alper
Health insurers finagling fees?
“For WellPoint, Math Error Spurs More Scrutiny”
by Avery Johnson, The Wall Street Journal, May 5, 2010
The health insurer WellPoint, an affiliate of Anthem Blue Cross, has decided to withdraw its request for up to a 39% price increase on individual plans in California.
The decision followed an actuarial consultant’s report about math errors in the company’s calculations. Alleged mistakes included overestimating future medical costs and double-counting the effect of aging on its policyholders.
The overestimation is thought to be related to a new requirement that health insurers spend “80% of their premium revenues on healthcare for plans that cover individuals and small businesses, and 85% for policies with large employers.”[1]
Health and Human Services Secretary Kathleen Sebelius has asked a nation-wide review of the health-related data on which costs are based, and she noted that $250 million has been allocated to states for that purpose.
Submitted by Margaret Cibes
Girls becoming less careful drivers
“Do Girls Speed More Than Boys?”
by Joseph B. White and Anjali Athavaley, The Wall Street Journal, May 5, 2010
Allstate Foundation has sponsored a survey that found that young women are not necessarily more responsible than young men – at least in their driving habits. An Allstate spokesman stated, “It would be fair to say the gap is closing,” although “teenage girls continue to be a better risk than boys.”
The data came from online interviews with 1,063 teens across the country in May 2009. About half of the girls felt that they are more likely to drive 10 mph over the speed limit or to phone/text while driving, compared to fewer than 40% of boys for each activity.
State Farm, the nation’s largest insurance company, charges 40% more for teenage boys than girls, down from a 1985 gap of 61%. While the company is raising the rates for teenage female drivers, it says that it is raising them based on claims experience and other factors, not these survey results.
For the current report, see “Shifting Teen Attitudes: 2009 State of Teen Driving”. For 2005 report, see “Chronic - A Report on the State of Teen Driving”. Unfortunately, neither the questionnaires, nor any raw data, appears to be available online.
Discussion
1. What additional information about the survey would you like to know in order to draw any conclusion about the driving habits of all teenage girls and boys across the country?
2. Do you believe that self-reporting by teenagers, in general is reliable? Would you expect a difference in relying on teen boys’ versus teen girls’ responses?
3. In the article, Progressive Direct quoted 6-month premiums for a boy and a girl in identical situations, including one speeding ticket apiece in the last 3 years, at $2,938 and $2,627, respectively. By what percent does the boy’s Progressive premium exceed the girl’s Progressive premium? How does it compare with Allstate’s 40% figure? Can you think of any reason(s) for the reported disparity?
4. The article referred to girls as becoming more “aggressive” drivers. If this is true, can you think of any reason(s) for this?
Submitted by Margaret Cibes