How many people are harmed versus helped by treatments

Posted on by July 15, 2014
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What fraction of people getting a particular medical treatment will be helped versus harmed?


Link: http://youtu.be/e_ytF2-4NkI

This is a follow-up to a previous commentary on the “number needed to treat” calculation mentioned in this previous post.

Here Dr Carroll offers in passing a more self-explanatory way of presenting a “number needed to treat.” If the “number needed to treat” is 50, for example, all that really says is that on average 1 out of every 50 people getting a particular treatment see a benefit from it.

He also contrasts this with the fraction harmed. If 1/50 are helped but 1/20 are seriously harmed, then maybe the treatment isn’t such a good idea. Of course, you also have to consider the nature of the benefit and the harm.

Incidentally, it’s easier to compare two fractions if both have the same numerator or both have the same denominator. For example, it’s easy to see that one in 50 is smaller than one in 20, and it’s also easy to see that 2 out of a hundred is smaller than 5 out of a hundred. But you might have to stop and think a second about how 1 in 50 compares with 5 out of 100.

A real world comparison I found very interesting appeared in a discussion of PSA testing on the National Cancer Institute website. According to an analysis taking into account data from two large studies, if 1000 men receive regular PSA testing a follow-up exams and treatment over the course of 10 years, then on average

  • 0 to 1 death from prostate cancer would be avoided.
  • 100 to 120 men would have a false-positive test result that leads to a biopsy, and about one-third of the men who get a biopsy would experience at least moderately bothersome symptoms from the biopsy.
  • 110 men would be diagnosed with prostate cancer. About 50 of these men would have a complication from treatment, including erectile dysfunction in 29 men, urinary incontinence in 18 men, serious cardiovascular events in 2 men, deep vein thrombosis or pulmonary embolism in 1 man, and death due to the treatment in less than 1 man.

This is a very informative comparison, though the conclusion remains ambiguous (and in any case, whether to get a PSA test is something to discuss with your doctor, not a decision to base on a website, especially given medical progress and the recent introduction of such things as MRI-guided biopsy).



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John Oliver on income inequality (updated)

Posted on by July 18, 2014
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I like Oliver’s stuff because he’s informative as well as funny:


Link: http://youtu.be/LfgSEwjAeno

A couple more points on the estate tax: As Oliver points out, only a microscopic proportion of estates — a mere 14 out of every 10,000 — pay any federal estate tax at all. He could have added that even for those estates, the tax applies only to the portion of the estate above the cutoff amount.

This same point is often misunderstood with respect to income tax. For example, single taxpayers with a taxable income over $406,750 in 2014 are in the 39.6 percent bracket, but they pay that tax rate only on the fraction of income that exceeds that cutoff. The rest of their income is taxed at multiple lower rates.

(And this is taxable income we’re talking about, after subtracting off deductions and what-not. In addition, most investment income income is taxed at a far lower rate. Also, unlike earned income, unearned income is not subject to Social Security tax.)

Back to the estate tax: Most of the value of large estates represents capital assets such as stocks, real estate, closely held businesses, etc. When heirs eventually sell the assets they inherit, they pay tax on the increase in value of those assets only since they inherited them. Any value increase before that point is not taxed at all. So the notion that the estate tax amounts to double taxation is nonsense.

Update: The post previously said that investment income isn’t subject to Medicare tax. As I belatedly remembered, that’s not quite true. One of the provisions of the Affordable Care Act is that net investment income is now subject to a 3.8 percent Medicare tax, but this applies only to people with a “modified adjusted gross income” above a certain limit, which is $200,000 for single taxpayers. The details can be found in a page on the IRS website.

In addition, it’s worth pointing out that the personal exemption phases out for very high-income individuals (which is mathematically equivalent to an additional tax in the income bad affected), and of course there’s a complication called the Alternative Minimum Tax.

Yes, this is unnecessarily complicated, and it would be good to simplify the personal income tax. Unfortunately, most “simplification” proposals considered by Congress in recent years involve reducing the number of tax brackets, which would not significantly simplify tax calculations at all but would have the effect of shifting more of the tax burden from the rich onto the middle class. If you’re wondering why that is, think about who it is who can afford to hire lobbyists.



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Aurora in real time

Posted on by July 14, 2014
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An aurora seen in northern Canada as captured on video in real time. That is, this is not time-lapse, it’s actually what auroras look like. I saw similar ones when I was stationed in Iceland.

Aurora Substorm – Real time motion from kwon, o chul on Vimeo.

Technically, of course, “aurora” is Latin for dawn. This phenomenon is more precisely an aurora borealis, a “dawn of the north.” Curiously, the sun can rise very nearly due north some days of the year as seen regions north of the arctic (or south of the antarctic) circle, so there can be a “northern (or southern) dawn” for real.



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Kids warn Canadians: Evacuate and take your fridges

Posted on by July 10, 2014
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According to this news report from some kids in Utah, it’s winter in Canada (it’s probably always winter in Canada), and unfortunately, a major snow tornado is apparently threatening the entire country, so if you’re anywhere in Canada, you should get out right now. There are more details on the evacuation order in the video:


Link: http://youtu.be/aO8Lk05NY8k

(OK, laugh, but it’s still more accurate than Fox News.)



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More human beings

Posted on by July 7, 2014
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A collection of videos of various people various places helping out, sometimes risking their own lives.


Link: http://youtu.be/oeph_eX_pVw

If you click through to YouTube you’ll find a bunch of similar videos, which will lead to a bunch more, and the heroes aren’t always humans. You’ll find humans rescuing dogs, for sure, but also dogs rescuing humans and dogs rescuing dogs. (And this isn’t anthropomorphizing.)



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How many people really benefit from various treatments

Posted on by May 18, 2015
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Pediatrician Aaron Carroll explains how to compute various measures of benefit for various health interventions, including drugs, diagnostic techniques, and diet. One of the most useful and easy-to-understand measures is the “Number Needed to Treat” (NNT), meaning the number of people you’d have to treat before you’d be reasonably confident of seeing one benefit (such as one life saved).


Link: http://youtu.be/eHxaDQNyfV4

His explanation of NNT might be a little confusing, so let me give an alternative version without formulas:

Suppose every science fiction fan has a 10 percent chance of getting Twonk’s disease (a legendary disease affecting fans). However, research shows that if you eat a hotdog every day for breakfast, the risk falls to just 3 percent.

So to put it another way, out of 100 people who don’t eat hotdogs for breakfast, you’d expect on average that 10 of them will likely come down with Twonk’s disease. But if you convince them all to eat hotdogs every morning, then (again, on average), only 3 of them would get it. So if 100 people change their diets, you’d expect 2 of them to benefit — the ones who otherwise would have contracted the disease.

So since treating 100 people on average benefits 2, treating 50 would presumably benefit 1. So the average “Number Needed to Treat” in order to benefit a single individual person is 50.

Now consider a drug that cuts the risk of some disease by 80 percent. That sounds really good! But suppose the risk in question is just 1 in a million to start with. So basically if you treated 100 million people, you’d prevent about 80 of them from getting the disease who otherwise would have. The NNT to benefit one person would be 100 million divided by 80, or about 1 1/4 million. It’s not at all obvious that it’s worth the trouble to take the drug, especially if it costs a lot of has serious side effects.



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Film Riot

Posted on by September 5, 2014
1

If you have any interest in filmmaking, this web series is definitely worth watching. Not only is it informative about equipment and techniques (lighting, special effects, etc.), it’s also often damned funny. It’s written and produced by Ryan Connolly and features his brother Josh, his sister Emily, and his friend Arris Quinones, among others. Thursday episodes typically begin with a funny sketch illustrating some effect or technique followed by an explanation of how it was achieved. Sometimes there’s a comic epilog (outtake, additional footage, joke, or whatever) at the very end. Here’s the latest episode, one of the best, in which Emily decides to try coffee:


Link: http://youtu.be/3yN4NusvfIg



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