Here’s yet another short video from pediatrician Aaron Carroll, this one venting annoyance at misleading or overhyped reports of medical research in the news media.
Incidentally, in this video Dr Carroll mentions belonging to a group of doctors who get together regularly to play board games, including role-playing games. Now keep in mind that Carroll is a pediatrician, a medical researcher, a writer whose work regularly appears in The New York Times, a blogger at The Incidental Economist, a YouTube personality, and a family man with a wife and kids. How in the 19,000 Anthedelian hells does he have time to play games? I’m not just amazed and curious, I’m really pretty annoyed. Does he just not sleep?
(Updated 2016 April 1 to add some additional point and try to improve the explanation below the video.)
Here’s a video with a surprise ending — a big surprise, in fact. The question addressed is this: What if you’re take a test for a disease and get a positive result. How worried should you be?
Obviously that depends on the seriousness of the disease and the reliability of the test. A little less obviously, it also depends on how common the disease is. To put some numbers on it, suppose it’s a pretty bad disease that effects one person in a thousand, that the test never misses a real instance of the disease, and that it’s reliable enough that only one healthy person in ten will get a positive result. (Note, incidentally, that since this hypothetical test is perfect at detecting the disease, a negative result means that you’re guaranteed not to have it.)
Here’s a video that analyzes the question using an important piece of mathematics called Bayes’s Theorem after the Reverend Thomas Bayes (1701-1761). Below the video I’ll give an alternative explanation that doesn’t require any probability theory:
OK, here’s the version without any algebra: Suppose we test a random group of a thousand people for the disease. Given that the disease effects only 1 in 1000 on average, we’d expect at most a few people in the group to have the disease, and it could be none at all.
The rest of the group, 999 on average, would not have the disease. But about 1/10 of them would get a positive result anyway, so we’d still expect roughly 100 positive results out of 1000 people even if none of them had the disease.
On average, then, we’d likely have about 100 false positives and 1 true positive. Of the positive test results, about 99 percent of them would likely be false positives. They could even all be false positives. And this is with a test that’s pretty accurate (only a 10% rate of false positive and a 0% rate of false negatives).
This is the problem with screening tests in general. Even with diseases that are less rare or tests that are even more accurate, there will be a lot of false positives. Besides the needless worries caused by false positives, there’s the chance that they might lead to medical interventions that are potentially harmful. This is why some screening tests are now discouraged as potentially leading to more harm than benefit.
And this doesn’t just apply to screening for diseases. Drug testing, for example, isn’t especially accurate, producing significant numbers of false positives. And while it’s true that the rate of drug abuse is a lot higher than one in a thousand, in practice a very high percentage of positive results are indeed false. Even when more accurate and expensive follow-up gas chromatography tests are employed, the number of false positives remains a problem.
This isn’t just a theoretical concern. A handful of states have passed laws requiring drug tests for poor people getting government assistance. That might at first glance seem like a good idea as a way to avoid having tax dollars go to support drug abuse. But in practice, the testing costs millions of dollars and produces a very small total number of positive results, resulting in no net savings. The substantial rate of false positives just makes it worse, and even true positives end up punishing not just drug users but their children. This isn’t an argument against policies to discourage drug abuse, only against bad policies that waste money that could be better spent directly on helping people get off drugs.
As noted in a previous post, North Carolina’s newest law is so ill-considered that it mandates the very thing is was supposedly meant to prevent. For example, the law (full text here) requires some men (complete with beards) to use women’s restrooms if their birth certificate identifies them as female and the restroom they’re using is in a state or local government building. On top of that, it cancels longstanding civil rights for North Carolinians, such as the right to sue in state court for discrimination in employment on the basis of race, religion, color, national origin, age, sex, or disability.
The poorly-thought-out law was adopted in irrational haste by a special one-day session of the far-right legislature and then immediately signed by the supposedly more moderate governor, Pat McCrory. There was an immediate explosion of condemnation from inside and outside the state from a wide swatch of the political spectrum and from civil rights groups, nonprofit and sports and academic organizations, and major businesses, including Duke University, the NCAA, the NBA, American Airlines, Wells Fargo, Disney, Microsoft, and Apple, among others. The people who operate the High Point Furniture Market, probably the largest trade show in the state, are pretty concerned and have issued a statement saying, “Dozens of customers have contacted the High Point Market Authority to inform us that they have canceled plans to attend the Market in April due to passage of HB2. There are also several campaigns on social media calling for a boycott of the High Point Market this spring.” If the law stays on the books it could be even worse next year, possibly leading to a permanent relocation.
In an effort at damage control, Governor McCrory’s administration released a statement (link) declaring the law to be a matter of “common sense,” but full of so many false assertions that when Raleigh’s WRAL television did a fact-check on that press release, they awarded it the lowest possible rating for accuracy. If anything, the article on WRAL’s website goes out its way to soften the criticism, but it still makes it clear that the administration’s statement is blatantly untrue.
For just one example, it claims that transgendered persons can still use the restrooms corresponding to their sex and sexual appearance simply by changing the sex given on their birth certificate. Changing the sex on one’s birth certificate is possible under limited circumstances for persons born in North Carolina and some other states, but it is not possible for those born in others, including Tennessee, the next state west.
And again, the law affects a much far range of people than the relatively tiny number of transgendered persons. (Most of them, I suspect, will simply ignore the law and continue to use the restroom that corresponds to their physical appearance. In fact, at least one legislator who voted for the law essentially said as much.) Vastly more people will be harmed by the law’s broader restrictions on civil rights.
(Updated 2016 May 8 to clarify that the restroom provisions apply only in state or local government buildings)
As you’ve no doubt heard, Donald Trump proposes to keep foreigners out of the country by building a high wall along the southern U.S. border. If you don’t think about it too hard, this might sound like a sensible idea, but in fact it’s remarkably dumb.
For one thing, the notion that the border is open is nonsense. The Obama administration has drastically expanded the size of the Border Patrol and has set record for deportations. The number of illegal immigrants in the U.S. is smaller now than it was a decade ago.
For another, the wall would cost billions upon billions to build and maintain, would create a number of major problems, and would not be all that effective. Which brings me to John Oliver’s hilarious piece on the subject.
I’m amazed and grateful that HBO uploads these clips to YouTube and allows them to be embedded for free. Of course, there’s more to John Oliver’s Last Week Tonight than these one-subject video essays. Even if you don’t have cable, you can now subscribe to HBO Now and watch their programming on line, which come to think of it I really need to get around to doing since besides John Oliver I’m a big fan of Game of Thrones. I’m not getting paid to say that, not even with a free subscription. (Which isn’t to say I’d turn it down, hint hint to any HBO folks who happen to see this.) George RR Martin doesn’t even pay me royalties for trying to look like me. You can watch free sample programs here, by the way.
Garry Shandling died Thursday at the age of 66, and that night Conan O’Brien talked about how Shandling helped him get past a personal crisis, partly as a consequence of a strange coincidence. There have been a lot of tributes to Garry Shandling, no doubt with more to come, but this one deserves a special mention.
Jackie and Dunlap ponder whether Trump is really as bad as Hitler, including the possibility that he might even be worse — a rich, Yankee Hitler. Some naughty four-through-six letter words here and there.
(Update 2016 March 28: The McCrory administration has produced a press release seriously misrepresenting the import on the law. More in this later post.)
(Update 2016 March 26: It turns out the new law also contains a provision canceling a long-established right to sue employers for any type of workplace discrimination (on the basis of race, gender, religion, etc.) in state court. People can still bring a civil rights action in federal court, of course, but that’s a lot more expensive, and there are a lot fewer federal courts. See this article at Talking Points Memo for more.)
As you may have read, the Republican-controlled North Carolina legislature held a one-day session for the sole purpose of passing a new law invalidating anti-discrimination and minimum-wage ordinances passed by localities. (For more details see for example this report.)
What particularly excited the legislators was the fact under a recent Charlotte ordinance, transgendered persons would be permitted to use the restroom of their gender identity. This is what happens in the real world most of the time anyway, and plenty of places in the U.S. the law explicitly permits it with no resulting problems.
In North Carolina, however, the new law requires people in state and local government buildings to choose a men’s or women’s restroom that corresponds to their sex as specified on their birth certificate, regardless how they dress or appear. People who have had a sex change can often get the birth certificate updated, but that depends on where they were born and it often doesn’t happen. Unless you’re a Republican legislator in North Carolina, you can see the obvious problem.
Here’s a picture of a man named J.P. Sheffield (Twitter handle @JayShef). Mr Sheffield”s birth certificate identifies him as female. So under the new North Carolina law, he has to start using the ladies’ room:
Transgender man JP Sheffield now required to use women’s rooms in NC
Great job, legislature!
(Updated 2016 May 8 to clarify that the restroom provisions apply only in state and local government buildings.)
I suspect most of you have seen this bit from NBC’s Saturday Night Live late last year, but in case you haven’t, here it is. Government officials question Kate McKinnon, Cecily Strong, and Ryan Gosling about their encounters with aliens. One of them apparently had a somewhat different experience with a lower class of alien. The funniest part about this might be the efforts of the other people in the scene not to laugh. This probably counts as mildly not safe for work, though SNL is of course a network show. I mean, it’s not like it’s pay cable.
Interesting brief video (under four minutes) about some things in our bodies that aren’t very useful but are left over in our DNA from our remote ancestors:
OK, one more from the folks who did the time machine and pirates bits. This one starts a little slow but gets better. Nothing great, but mildly amusing, and I rather like harmless pranks like these:
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