Video of the day

I saw this on FB a few times but didn’t watch until my wife posted on my wall.  I must admit I do love What Would You Do.  There’s a number of these but the one starting 4:45 in is truly awesome.

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Dumbest public health campaign ever

Despite beliefs to the contrary, most Americans do just fine on getting the amount of water they need.  The body has this little mechanism called “thirst” and is an excellent homeostasis machine.  And we’re not exactly lacking for access to water here in the US.  Yet, Michelle Obama is apparently pushing a drink more water campaign with the help of a gullible media that doesn’t give a wit for actual science.  That whole 8 glasses a day thing?  I’m pretty sure I’ve explained before that’s a total myth.  And, it would be one thing if the campaign were about replacing unhealthy beverages with water, but it’s simply telling people to consume more water.  That’s stupid.  James Hamblin in the Atlantic:

Obama’s appearance today is just part of the campaign’s “bi-lingual day of water messages on a dozen TV shows … which will involve hosts drinking water and encouraging viewers to drink water.” The shows include Today, Good Morning America, The View, Live With Kelly and Michael, Late Night, The Tonight Show, The Late Show, The Doctors, and Rachel Ray. All will feature “Drink up” messages.

Why? That is the question.

“40 percent of Americans drink less than half of the recommended amount of water daily,” said Sam Kass, White House senior policy advisor for nutrition policy [sic?], yesterday. Kass and Mrs. Obama’s press secretary Hannah August attributed that statistic to a CDC study.

The problem is, though, that there is no recommended daily amount of water. If we knew how much we should be drinking, and it turned out we weren’t drinking enough, then yes, tell us to drink more. If they were telling us to replace soda in our diets with water, that would also be reasonable and potentially productive. They’re explicitly not doing that, though.  [emphasis mine] …

Here is that “adequate intake” recommendation from the Institute of Medicine. The Mayo Clinic’s recommendation is “If you drink enough fluid so that you rarely feel thirsty and produce 1.5 liters (6.3 cups) or more of colorless or light yellow urine a day, your fluid intake is probably adequate.” Not that you have to measure your urine every day, but you get it. The Institute of Medicine likewise sidesteps quantified intake guidelines and takes an Al Jones-esque approach: “Let thirst be your guide.” That’s what most doctors will tell you, too.

As a general rule, I think it is great that Mrs. Obama is using her bully pulpit to encourage good health, especially among kids.  I just really wish she would stick to doing it ways that are actually based upon science.

About that budget analogy

Republicans just love to use the household budget analogy for government despite how wildly inappropriate it is.  Over at Wonkblog, Brad Plumer does a great job of showing just how non-sensical this really is:

The idea here seems to be that the U.S. government is taking on a lot of debt. True, the typical American family also takes on lots of debt through mortgages and the like — the median debt burden is about $70,000 — but U.S. government borrowing is even more massive than that.

Fair enough. This analogy seems incomplete, though. We should take it further. If the typical family — let’s call them the Smiths — really did spend like the federal government, a few other things would also be true:

– The Smiths would spend 20 percent of their budget, or $12,800 each year, on an arsenal of guns, tanks and drones to defend their house against threats or to invade the occasional neighbor over lawn-pesticide disputes and access to the gas station.

– The Smiths would spend another third of their income financing retirement and health care for Grandma and Grandpa. Part of that would have been prepaid by money that Grandma and Grandpa socked away while they were working, but some of it would be paid for by the parents and kids who are chipping in.

– Actually, come to think of it, the Smiths spend nearly half their money — 43 percent — operating a massive insurance conglomerate whose main beneficiaries are family members.

– Over the past few years, the Smiths have been able to borrow a vast amount of cash at negative interest rates. Banks have essentially been paying the family to hold their money. That’s partly because everyone assumes the Smiths are more or less immortal and will always be good for it. They’re the wealthiest, most dependable familyin a neighborhood full of upstarts and imploding Greek restaurants. Plus they have all those tanks.

– The Smiths, by the way, own their own printing press. For whatever reason, it’s totally legal for them to print more money, although they have to be selective about this. This makes it very unlikely that they’d ever default.

– Of the $312,000 that the Smith parents have borrowed so far, about 47 percent of that is owed to outsiders, including the Chens down the street. But much of the rest they borrow from their kids with a promise to repay.

– The Smiths could also, crucially, tap into the kids’ extra income from their lucrative million-dollar lemonade stand business if they ever wanted to whittle down the debt, although this would come up for a family vote and the kids aren’t keen on this.

Anyway, it’s a good analogy. The U.S. federal government really does resemble your typical money-printing family that owns lots of tanks, operates a giant insurance conglomerate, can borrow money at extremely low rates, and is assumed to be immortal.  [emphasis mine]

Who are the best college teachers?

I meant to link to this Atlantic summary of new research that suggests tenured professors (i.e., people like me) are actually worse college teachers than adjuncts and graduate student instructors.  I forgot, until reminded by a adjunct/graduate student instructor friend.  So, here goes:

We all know the stereotype about tenured college professors: great researchers, lazy teachers. After all, you don’t get tenure by dazzling 18-year-olds with PowerPoints. You do it by convincing other academics you’re a genius in your field who’s going to bring boatloads of grant money and prestige to campus. And nobody ever won a grant by grading papers.

A gross oversimplification? Of course. But there might also be a hint of truth in the caricature, at least judging by a new study from Northwestern University. The paper–co-authored by university president Morton Schapiro, professor David Figlio, and consultant Kevin Soter of The Greatest Good–finds that faculty who aren’t on the tenure-track appear to do a better job than their tenured/tenure-track peers when it comes to teaching freshmen undergraduates…

Previous studies have suggested that colleges tend to hurt their graduation rates by hiring more part-time and non-tenure faculty. But Shapiro and his team wanted to measure the impact of tenure on “genuine student learning,” a notoriously tricky task. So how’d they do it? Using the transcripts of Northwestern freshmen from 2001 through 2008, the research team focused on two factors: inspiration and preparation.

To start, the team asked if taking a class from a tenure or tenure-track professor in their first term later made students more likely to pursue additional courses in that field. So, to borrow their example, if an undergrad took economics 101 from an adjunct, and political science 101 from a tenured professor, were they any more likely to sign up for additional poli sci classes. That’s the inspiration part. Second, the researchers wanted to know if students who took their first course in a field from a tenure or tenure-track professor got better grades when they pursued more advanced coursework. So, if our hypothetical student took more classes in both economics and poli sci, what did they fare better in? That’s the preparation part.

Turns out, tenured and tenure-track professors underperformed on both the inspiration and preparation fronts. Controlling for certain student characteristics, freshmen were actually about 7 percentage points more likely to take a second course in a given field if their first class was taught by an adjunct or non-tenure professor.* They also tended to get higher grades in those future courses…

As the study notes, these patterns held “for all subjects, regardless of grading standards or the qualifications of the students the subjects attracted…” In other words, the non-tenure-track faculty bested their more established colleagues every from English to Engineering.

Many caveats follow.  Short version: this is not exactly representative of college teaching more broadly.  That said, there’s probably a there there.  As Weissman concludes:

That said, there is something appealingly intuitive in these results. Professionals who are paid entirely to teach, in fact, make for better teachers. Makes sense, right?

Mostly, this just raises a lot more questions for me.  Most importantly, I think the nature of the institution is hugely important.  This probably is true at large research institutions where tenure and promotion have very little to do with teaching.  But, it’s certainly my experience that one improves at teaching with experience and, on average, tenured professors are going to have a lot more.  Perhaps, if those tenured professors were actually recognized and rewarded more for their quality teaching, they could actually invest the time and emotional energy to be a lot better at it.  But they won’t be at research universities.  An adjunct, though, who is not a good teacher, is out on his butt pretty fast in many places.  He doesn’t have an Oxford book to save him.

I’d also really like to see the variance in a larger sample.  I would not be surprised if adjuncts really do get a higher mean in a broader study, but I strongly suspect the very best (and sadly, very worst) teachers are actually going to be tenured professors.

How to think like a social scientist when you’re pregnant

In a recent quick hits, I made brief mention of Economist Emily Oster’s new book on pregnancy that actually looks at evidence for all the things we tell pregnant women not to do and places them in an appropriate cost/benefit framework.  Apparently, some people don’t like being told that there’s really no evidence that light drinking during pregnancy will harm your baby when they just know otherwise that any woman who drinks at all during pregnancy is a horrible person destined for a defective baby.  Who needs research, evidence, or other such silly things.   Anyway, apparently Oster has been taking a huge amount of flack for the alcohol and pregnancy thing and has a nice response to it all in Slate:

I reviewed many, many studies, but I focused in on ones that compare women who drank lightly or occasionally during pregnancy to those who abstained. The best of these studies are ones that separate women into several groups—for example: no alcohol, a few drinks a week, one drink a day, more than one drink a day—and that limit the focus to women who say they never had a binge drinking episode. With these parameters, we can really hone in on the question of interest: What is the impact of having an occasional drink, assuming that you never overdo it?

I summarize two studies in detail in my book: one looking at alcohol consumption by pregnant women and behavior problems for the resulting children up to age 14 and one looking at alcohol in pregnancy and test performance at age 14.  Both show no difference between the children of women who abstain and those who drink up to a drink a day. I summarize two others in less detail: one looking at IQ scores at age 8 and a more recent one looking at IQ scores at age 5. These also demonstrate no impact of light drinking on test scores.

I argue that based on this data, many women may feel comfortable with an occasional glass of wine—even up to one a day—in later trimesters. (More caution in the first trimester—no more than two drinks a week—because of some evidence of miscarriage risk.)

Like alcohol, Tylenol, caffeine, and anti-nausea drugs like Zofran are substances that—in moderation—are thought to be safe during pregnancy. But they are also substances that in excessive doses could be dangerous. Some women decide that they will therefore avoid them altogether because they cannot be sure. And many women, seeing the evidence in the book on alcohol, will still choose to avoid it…

People ask, “Why take the risk?” since there is no benefit to the baby. But this ignores the fact that we are always making choices that could carry some risk and have no benefit to the baby. Driving in a car carries some risk to your baby, and your fetus does not benefit from that vacation you took. Or they ask, “Is it so hard to give up drinking for nine months?” The answer is, of course, no, but because you might enjoy the occasional beer, it seems worth at least asking the question about the risks…

But others will see the data, like the data on caffeine or Tylenol, and choose to have an occasional drink, as I did. The value of the data is not that it leads us all to the same choice, just that it introduces a concrete way to make that choice.

Not expecting any more pregnancies in my life I don’t think I’ll actually read the book, but as a ruthless empiricist, I love what Oster is attempting to do here.  We could all think a lot more rationally and a lot more evidence-based on many aspects of health and our behavior.

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