Archive for Language of science

When 90% is 32%

I've occasionally complained that when it comes to comparing sampled distributions, modern western intellectuals are mostly just as clueless as the members of the Pirahã  tribe in the Amazon are said to be with respect to counting (see e.g.  "The Pirahã and us", 10/6/2007).  And it doesn't take high-falutin concepts like "variance" or "effect size" to engage this incapacity — simple percentages are often enough.

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(Mis-) Interpreting medical tests

Jon Hamilton, "Alzheimer's Blood Test Raises Ethical Questions", NPR Morning Edition 3/9/2014:

An experimental blood test can identify people in their 70s who are likely to develop Alzheimer's disease within two or three years. The test is accurate more than 90 percent of the time, scientists reported Sunday in Nature Medicine.

The finding could lead to a quick and easy way for seniors to assess their risk of Alzheimer's, says Dr. Howard Federoff, a professor of neurology at Georgetown University. And that would be a "game changer," he says, if researchers find a treatment that can slow down or stop the disease.  

But because there is still no way to halt Alzheimer's, Federoff says, people considering the test would have to decide whether they are prepared to get results that "could be life-altering." 

But  having a prediction with no prospect for a cure is not, in my opinion, the biggest problem with tests of this kind.

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The inclusion epidemic

Last week, a journalist asked me a question in connection with the recent flurry of stories on changes in childhood obesity percentages in the period from 2001 to 2012. When I looked into it, what struck me was that a category defined as "BMI at or above the 95th percentile" applied to about 15-17% of the population throughout the period discussed.

This sounds like a statistical approximation to Garrison Keillor's joke about his home town, where "all of the children are above average". But the normative percentiles are based on data from an earier time, and so it's perfectly logical that 17.1% of the age-2-19 sample in the 2003-2004 period should be at or above the 95th percentile for the 1963-1994 period. This is just a symptom, after all, of the famous "obesity epidemic".

Still, I remained curious about just when this large change really took place. (Most of) the raw data is available on line from the CDC, and I decided to spend an hour or so satisfying my curiosity about what is going on here: has there actually been a gradual climb over 50 years, which looks steep when a threshold derived from 1963-1994 is used for data from 2003 to the present? Or was there a steeper climb over a narrower stretch of time?

I found a clear answer to this question. But when I looked into it further, I found some additional information that made me wonder whether there has really been any change over time at all.

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(Not) trusting data

Pete Warden, "Why you should never trust a data scientist", 7/18/2013:

The wonderful thing about being a data scientist is that I get all of the credibility of genuine science, with none of the irritating peer review or reproducibility worries. [...]

I’ve never ceased to be disturbed at how the inclusion of numbers and the mention of large data sets numbs criticism. The articles live in a strange purgatory between journalism, which most readers have a healthy skepticism towards, and science, where we sub-contract verification to other scientists and so trust the public output far more. If a sociologist tells you that people in Utah only have friends in Utah, you can follow a web of references and peer review to understand if she’s believable. If I, or somebody at a large tech company, tells you the same, there’s no way to check. The source data is proprietary, and in a lot of cases may not even exist any more in the same exact form as databases turn over, and users delete or update their information. Even other data scientists outside the team won’t be able to verify the results. The data scientists I know are honest people, but there’s no external checks in the system to keep them that way.

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The Afterlife Ethnographic Survey

Franz Boas has a facebook page, whose contents suggest that his acumen is undimmed by death. A couple of weeks ago, one of his facebook friends asked this:

When Freud gave his famous "introductory lectures" at Clark University in 1909, Boas was a faculty member at the same university. I wonder if he attended the lectures? I have read some off-hand comments in Franz Boas's writing indicating that apparently he didn't think much of Freud. But does anyone know of any more in-depth historical accounts of this (missed?) encounter between papa Freud and papa Boas? Thank you hive mind!!!

Boas responded:

When I read Totems and Taboos I thought it was one of the most brilliant parodies ever written. You can imagine my surprise when I learned that Sigmund was serious about all that elders urinating on the fire nonsense. Such flights of fancy, imposing Victorianism on the human subconscious as a human universal. He has not fared well here in the afterlife, last time I saw him he was living in a van down by the river with L. Ron Hubbard.

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"Significance", in 1885 and today

There's an ongoing argument about the interpretation of Katherine Baicker et al., "The Oregon Experiment — Effects of Medicaid on Clinical Outcomes", NEJM 5/2/2013, and one aspect of this debate has focused on the technical meaning of the word significant. Thus Kevin Drum, "A Small Rant About the Meaning of Significant vs. 'Significant'", Mother Jones 5/13/2013:

Many of the results of the Oregon study failed to meet the 95 percent standard, and I think it's wrong to describe this as showing that "Medicaid coverage generated no significant improvements in measured physical health outcomes in the first 2 years."

To be clear: it's fine for the authors of the study to describe it that way. They're writing for fellow professionals in an academic journal. But when you're writing for a lay audience, it's seriously misleading. Most lay readers will interpret "significant" in its ordinary English sense, not as a term of art used by statisticians, and therefore conclude that the study positively demonstrated that there were no results large enough to care about.

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Importance of publishing data and code

J.W. writes:

In connection with some of your prior statements on the Log about the importance of publishing underlying data, you might be interested in Thomas Herndon, Michael Ash, and Robert Pollin, "Does High Public Debt Consistently Stifle Economic Growth? A Critique of Reinhart and Rogoff", PERI 4/15/2013 (explanation in lay language at "Shocking Paper Claims That Microsoft Excel Coding Error Is Behind The Reinhart-Rogoff Study On Debt", Business Insider 4/16/2013). In sum, a look at the data spreadsheet underlying a really influential 2010 economics paper reveals that its results were driven by selective data exclusions, idiosyncratic weighting, and an Excel coding error [!].

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More journalists with reading disabilities

Or maybe this is about press-release writers who don't express themselves clearly. According to "Chemical in Tap Water Linked to Food Allergies", Drugwatch 12/7/2012 (emphasis added, here and throughout):

A new study in the Annals of Allergy, Asthma and Immunology links high levels of dichlorophenols–chemicals used for chlorinating tap water–to a higher risk of food allergies. According to the study, people with higher levels of these chemicals in their urine have a greater risk of developing food allergies.

Out of the 2,211 people with high levels of dichlorophenols who participated in the study, 411 had food allergies and 1,016 had an environmental allergy, according to researchers.

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Psycho kids today

Kevin Dutton, "Psychopathy's Double Edge", Chronicle of Higher Education 10/22/2012:

[I]n a survey that has so far tested 14,000 volunteers, Sara Konrath and her team at the University of Michigan's Institute for Social Research has found that college students' self-reported empathy levels (as measured by the Interpersonal Reactivity Index, a standardized questionnaire containing such items as "I often have tender, concerned feelings for people less fortunate than me" and "I try to look at everybody's side of a disagreement before I make a decision") have been in steady decline over the past three decades—since the inauguration of the scale, in fact, back in 1979. A particularly pronounced slump has been observed over the past 10 years. "College kids today are about 40 percent lower in empathy than their counterparts of 20 or 30 years ago," Konrath reports.

As is all too often true for stories about results in social psychology — and especially stories about the Problems with Kids Today — this one is misleading in almost every particular.

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Dinosaurs, baboons, and science journalists

It is well known within organic chemistry circles that there is a very strong bias toward L rather than D homochirality in the structure of earth's organic compounds. A recent paper offered a speculation about a possible explanation of the bias:

If there was … right circularly polarized light with energy in the uv or higher irradiating the asteroid belt when the amino acids were present on a particle that later came to Earth, this could account for the small excesses of the L anantiomers seen in the α-methyl amino acids.

And what did the PR/media machine do to make news out of this finding? The headlines ultimately mutated as far as this:

Claim: Advanced dinosaurs may rule other planets

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From wraith to smoking duck

I previously described the evolution of the Higgs Boson from Leon Lederman's "wraithlike presence throughout the universe that is keeping us from understanding the true nature of matter", perhaps bowdlerized by his editors from "the goddamn particle" to "the God particle", and onwards to Dennis Overbye's "kind of cosmic molasses [...] that would impart mass to formerly massless particles trying to move through it like a celebrity trying to get to the bar".

Yesterday, the high-energy euphoria at CERN seems to have excited some really exotic metaphorical resonances, combining the elementary building-blocks of cultural cognition in ways not normally seen on earth.

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Neutral Xi_b^star, Xi(b)^{*0}, Ξb*0, whatever

Carl Franzen, "Big Bang Machine Discovers Brand New Particle", TPM IdeaLab 4/27/2012:

An entirely new type of particle has been discovered by scientists using the world’s largest and most powerful particle accelerator, the Large Hadron Collider (LHC), near Geneva, Switzerland.

The discovery of the new particle, called “neutral Xi_b^star baryon,” was made by the CMS experiment, one of six separate particle physics experiments running at the LHC. It was announced Friday by Symmetry Magazine.

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Neuroscience

Ferris Jabr reports on a press conference where neuroscientists try to come to terms with some of the problems in their discipline that we've covered over the past few years ("Neuroscientists: We Don’t Really Know What We Are Talking About, Either", Scientific American 4/1/2012):

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Novel illness name of the week

News is leaking out about DSM-5, the new edition of the Diagnostic and Statistical Manual of Mental Disorders, the central reference book of mental illnesses for the psychiatric profession, due to be published in May 2013. Journalists who have been delving into the details of its proposed new listings (it is up for comment by the medical community at the moment) are finding rich pickings in jargon-encapsulated official names for new mental conditions. I think my vote for new illness name of the week has to go to disruptive mood dysregulation disorder. This would be the new DSM-5 term for temper tantrums. Is your child (or indeed, your domestic partner) sicker than you thought?

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Gyromodels of everything

"Radical theory explains the origin, evolution, and nature of life, challenges conventional wisdom: Case Western Reserve theorist develops incomparable model that unifies physics, chemistry, and biology", Case Western Reserve press release 1/26/2012:

The earth is alive, asserts a revolutionary scientific theory of life emerging from Case Western Reserve University School of Medicine. The trans-disciplinary theory demonstrates that purportedly inanimate, non-living objects—for example, planets, water, proteins, and DNA—are animate, that is, alive. With its broad explanatory power, applicable to all areas of science and medicine, this novel paradigm aims to catalyze a veritable renaissance.

Erik Andrulis, PhD, assistant professor of molecular biology and microbiology, advanced his controversial framework in his manuscript "Theory of the Origin, Evolution, and Nature of Life," published in the peer-reviewed journal, Life. His theory explains not only the evolutionary emergence of life on earth and in the universe but also the structure and function of existing cells and biospheres.

In addition to resolving long-standing paradoxes and puzzles in chemistry and biology, Dr. Andrulis' theory unifies quantum and celestial mechanics. His unorthodox solution to this quintessential problem in physics differs from mainstream approaches, like string theory, as it is simple, non-mathematical, and experimentally and experientially verifiable. As such, the new portrait of quantum gravity is radical.

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