Poverty and Dentistry

May 31, 2016
Posted by Jay Livingston

A couple of years ago, Marco Rubio (remember him?), the Heritage foundation, and others were making the ludicrous claim that if poor people would just get married, the rate of child poverty would fall by 80% or more. After all, a very large proportion of children in poverty lived in single-parent homes. These conservatives were mistaking correlation for cause, and the causal arrow might easily point the other way. When most of the men in sight are poor and without prospects for improving their lot, a woman with children might well choose to remain unwed. So instead of non-marriage leading to children in poverty, it is the general poverty of a population that makes for lower rates of marriage. 

To illustrate the folly of taking correlation as cause, I used the example of dentistry. People who go to the dentist are much less likely to be poor, and the poor were twice as likely to be toothless. By the logic of marriage-ends-poverty, we could conclude that visiting the dentist once a year would lower a person’s probability of being poor by 50%. (That blog post is here. )

I was being facetious about cause and effect. But it turns out that while dentistry may not cause prosperity, poor people think it’s important. Richard Reeves at The Brookings Institute (here) looks at reports on Colorado, a state where expansion of healthcare under Obamacare and Medicaid included dental coverage for those with incomes under $30,000.

Did low-income people take advantage of their new medical and dental benefits? No and yes, respectively. The Colorado Health Access Survey found that from 2009 to 2015, the rate of low-income Coloradans visiting the doctor changed only slightly. But visits to the dentist were another matter.

(Click on an image for a larger view.)

As the percent of low-income people with dental coverage rose to about 63%, the percent who actually visited the dentist rose to nearly that same proportion.

Reeves offers no explanation for why the poor were so much more likely to use their dental coverage than their medical. Perhaps it’s because the pain of a toothache is hard to ignore. Also, with many medical symptoms, a visit to the doctor is only the beginning, and the symptom improves gradually, with medications, treatments, and other regimens, But the pain of a toothache can be ended with a single visit to the dentist.

The Face That Launched a Thousand False Positives

May 27, 2016
Posted by Jay Livingston

What bothered the woman sitting next to him wasn’t just that the guy was writing in what might have been Arabic (it turned out to be math). But he also looked like a terrorist. (WaPo story here.)

We know what terrorists look like. And now an Israeli company, Faception, has combined big data with facial recognition software to come up with this.

According to their Website:

Faception can analyze faces from video streams, cameras, or . . . databases. We match an individual with various personality traits or types such as an Extrovert, a person with High IQ, Professional Poker Player or a Terrorist.

My first thought was, “Oh my god, Lombroso.”

If you’ve taken Crim 101, you might remember that Lombroso, often called “the father of criminology,” had the idea that criminals were atavisms, throwbacks to earlier stages of human evolution, with different skull shapes and facial features. A careful examination of a person’s head and face could diagnose criminality – even the specific type of lawbreaking the criminal favored. Here is an illustration from an 1876 edition of his book. Can you spot the poisoner, the Neapolitan thief, the Piedmont forger?

(Click on the image for a larger view.)

Criminology textbooks still mention Lombroso, though rarely as a source enlightenment. For example, one book concludes the section on Lombroso, “At this point, you may be asking: If Lombroso, with his ideas about criminal ears and jaws, is the ‘father of criminology,’ what can we expect of subsequent generations of criminologists?”

Apparently there’s just something irresistible in the idea that people’s looks reveal their character. Some people really do look like criminals, and some people look like cops.* Some look like a terrorist or a soccer mom or a priest. That’s why Hollywood still pays casting directors. After all, we know that faces show emotion, and most of us know at a glance whether the person we’re looking at is feeling happy, angry, puzzled, hurt, etc. So it’s only logical that a face will reveal more permanent characteristics. As Faception puts it, “According to social and life science research, our personality is determined by our DNA reflected in our face.” It’s not quite true, but it sounds plausible.

The problem with this technique is not the theory or science behind it, and probably not even its ability to pick out terrorists, brand promoters, bingo players, or any of their other dramatis personae in the Faception cast of characters. The problem is false positives. Even when a test is highly accurate, if the thing it’s testing for is rare, a positive identification is likely to be wrong. Mammograms, for example, have an accuracy rate as high as 90%. Each year, about 37 million women in the US are given mammograms. The number who have breast cancer is about 180,000. The 10% error rate means that of the 37 million women tested, 3.7 million will get results that are false positives. It also means that for the woman who does test positive, the likelihood that the diagnosis is wrong is 95%.**

Think of these screening tests as stereotypes. The problem with stereotypes is not that they are wrong; without some grain of truth, they wouldn’t exist. The problem is that they have many grains of untruth – false positives. We have been taught to be wary of stereotypes not just because they denigrate an entire class of people but because in making decisions about individuals, those stereotypes yield a lot of false positives.  

Faception does provide some data on the accuracy of its screening. But poker champions and terrorists are rarer even than breast cancer. So even if the test can pick out the true terrorist waiting to board the plane, it’s also going to pick out a lot of bearded Italian economists jotting integral signs and Greek letters on their notepads.

(h/t Cathy O’Neil at MathBabe.org)
----------------------

* Some people look like cops. My favorite example is the opening of Richard Price’s novel Lush Life – four undercover cops, though the cover they are under is not especially effective.

The Quality of Life Task Force: four sweatshirts in a bogus taxi set up on the corner of Clinton Street alongside the Williamsburg Bridge off-ramp to profile the incoming salmon run; their mantra: Dope, guns, overtime; their motto: Everyone’s got something to lose.  [...] At the corner of Houston and Chrystie, a cherry-red Denali pulls up alongside them, three overdressed women in the backseat, the driver alone up front and wearing sunglasses. The passenger-side window glides down . “Officers, where the Howard Johnson hotel at around here ...” “Straight ahead three blocks on the far corner,” Lugo offers. “Thank you.” [. . .] The window glides back up and he shoots east on Houston. “Did he call us officers?” “It’s that stupid flattop of yours.” “It’s that fuckin’ tractor hat of yours.”

It wasn’t the haircut or the hat. They just looked like cops.

** The probability that the diagnosis is correct is 5% – the 180,000 true positives divided by the 3.7 million false positives plus the 180,000 true positives – roughly 180,000 / 3,900,000. (I took this example from Howard Wainer’s recent book, Truth and Truthiness.)

A Time for Cliches

May 25, 2016
Posted by Jay Livingston

You can imagine what the reaction on the right would be if students heckled their graduation speaker with shouts of “Trash” and “Get off the stage.” Actually, you don’t have to imagine. You can find what  the National Review, the Wall Street Journal, and similar conservative havens have already said – that campus liberals are against free speech and that they are afraid to even hear ideas they disagree with.

Will they say those same things about the students at Cal State Fullerton who erupted during a graduation ceremony at the College of Communications. The speaker was Maria Elena Salinas, an anchor at Univision, At one point, she spoke briefly in Spanish “to encourage students interested in going into Spanish-language media and to tell them she has a scholarship for them,” (WaPo) The Fullerton student body is 40% Hispanic.

Tensions worsened as Salinas began offering advice to journalism students to use the tools of media to rebut political figures such as Donald Trump. That’s when folks began yelling things to Salinas such as, “Get off the stage!” and “Trash!” (OC Weekly )

Were these students* against free speech? Were they afraid to hear her ideas about Trump? I doubt it. I can only repeat what I said a year ago at graduation time (here): graduations are not about the exchange of ideas, they are about symbolism, and what the ritual, almost any ritual, symbolizes is group solidarity. Conflict is out place. If a speaker represents policies that are highly divisive, or if the speech becomes explicitly partisan, or if the speaker excludes part of the assembled group (e.g., by speaking a language half the group cannot understand), the temporary unity is ruined. The students who heckled Salinas probably felt that she had a right to her opinions and her language, but this was their graduation ceremony, and she was spoiling the show.

I guess there’s something to be said for tepid speeches with their cliches about hard work and achievement, about the future and seizing opportunity, about following your passion and making a difference and all those other phrases on your Commencement Speech Bingo card.

-----------------------
* The students who voiced their displeasure must have been a small minority and seated away from the microphone. In the video in the WaPo link, their heckling cannot be heard. If you watch the video excerpt, you can also hear that the Spanish portion of the speech took less than thirty seconds. So possibly the Post is making a bigger deal out of this than is warranted.

Is It Trivia?

May 21, 2016
Posted by Jay Livingston

 Is knowledge important? Or in the age of the Internet, is it all just trivia?

1. A quiz posted on Facebook says “97% of Adults Can’t Pass This Elementary Test (21 Questions).” What is the closest planet to the sun is, where was Einstein was born, which president served three consecutive terms. . . .

I could answer most of the questions. But instead of basking in the glow of the screen’s telling me I was a genius, or being horrified that so many of my fellow Americans flunked, I was bothered by the more important question: so what? What’s the point of knowing facts like these? Unless you’re going to be on Jeopardy, does it matter any more? Most of the 97% do not need to know which planet is closest to the sun, and if they did ever need that information, they could find it on the Internet.

And yet, I probably use someone’s knowledge of stuff like this as a proxy for their ability to think.

2.  Most multiple-choice exams are based on this same assumption – that students who can remember more facts are better students. Years ago I was discussing this with an economics adjunct who had an office near mine.  “Why not use multiple-choice tests for grading?” I said. “If you used some other kind of test, you’d get the same results.”

    “Then why not just ask them their parents’ income?” he said. “You’d get the same distribution.”

3. I told one of my classes that they could choose the kind of final they wanted: open book – meaning books, notes, phones, whatever – or traditional. With open book, I warned, the questions will be harder– not just giving a definition or fact. Even the multiple-choice items will require you to think. I gave them this free sample:

A Mastercard ad shows a father and son at a baseball game.  The voiceover says, “Two tickets $46. Two hot dogs, two popcorns, two sodas $27. One autographed baseball $50.  Real conversation with eleven-year-old son, priceless.”  The idea that conversation with your own son is “priceless” – that its value cannot be put into dollars – means that its value is     a.    worthless     b.    utilitarian     c.    universalistic     d.    particularistic

Besides, I said, looking up stuff on the Internet or in your books, notes, or downloaded PowerPoints takes time, time that you’ll need for writing.

“So now, how many want open book?” I asked. Hands flew up. It wasn’t even close.

4. Question #10 on the Facebook quiz:

More trivia, important, if at all, only because the US is still stuck with its pre-metric system.

The day after I took this test, I was in the locker room at the gym. One guy there had an empty three-liter Poland Spring jug, He must have been about to use it to mix up some energy elixir. He was asking his friend how many ounces in a gallon, wondering, I guess, if the jug would be large enough. The directions for the magic powder he’d bought probably told him to mix so many scoops with one gallon of water. 

The label said three liters or 101.4 ounces.  The friend was pretty sure that a gallon was 162 ounces. Oh, well. When it’s time to mix the cocktail, they can look it up on their smart phones. And if they don’t, the guy with the jug didn’t look like someone whose buffness would suffer much from a potion that, like his general knowledge, was too diluted.