Correlation and Causality: Flu Shots

We've known for a long time that people who get flu shots are a lot less likely to die during flu season compared to people who do not.  But is the flu vaccine really responsible for this?

Jackson's findings showed that outside of flu season, the baseline risk of death among people who did not get vaccinated was approximately 60 percent higher than among those who did, lending support to the hypothesis that on average, healthy people chose to get the vaccine, while the "frail elderly" didn't or couldn't. In fact, the healthy-user effect explained the entire benefit that other researchers were attributing to flu vaccine, suggesting that the vaccine itself might not reduce mortality at all.

That quote is from this Atlantic article, which has a good analysis of the (rather sparse) medical evidence behind vaccines.  It includes the following paragraph:

The annals of medicine are littered with treatments and tests that became medical doctrine on the slimmest of evidence, and were then declared sacrosanct and beyond scientific investigation. In the 1980s and '90s, for example, cancer specialists were convinced that high-dose chemotherapy followed by a bone-marrow transplant was the best hope for women with advanced breast cancer, and many refused to enroll their patients in randomized clinical trials that were designed to test transplants against the standard—and far less toxic—therapy. The trials, they said, were unethical, because they knew transplants worked. When the studies were concluded, in 1999 and 2000, it turned out that bone-marrow transplants were killing patients. Another recent example involves drugs related to the analgesic lidocaine. In the 1970s, doctors noticed that the drugs seemed to make the heart beat rhythmically, and they began prescribing them to patients suffering from irregular heartbeats, assuming that restoring a proper rhythm would reduce the patient's risk of dying. Prominent cardiologists for years opposed clinical trials of the drugs, saying it would be medical malpractice to withhold them from patients in a control group. The drugs were widely used for two decades, until a government-sponsored study showed in 1989 that patients who were prescribed the medicine were three and a half times as likely to die as those given a placebo.

I've known for some time that doctors are not scientists.  They generally know nothing about the scientific method: testing theories against evidence.  Their actions have almost nothing to do with data, or statistics, or how to truly uncover truth.  They simply guess, and then claim that their guesses are beyond questioning.  Studies have shown that the treatments doctors prescribe are based not on evidence, but on what other doctors around them are doing.

The only thing you can say in their defense is that all of the 'alternative medicine' out there is even worse.  What is it about medical care that makes people act so irrationally?

I found Jackson's vaccine study via Google Scholar, and read it.  It looks like a good piece of science, but there are a few things in there I do not know how to interpret properly.  I've asked one of the professors in our departments, a statistics expert, for his opinion on the article.  Unless he finds a serious problem in the study, it is probably safe to say that flu vaccines really don't do much to prevent mortality in people older than 65.

Note that the study only looked at death rates in old people.  It may still be true that vaccinating young people, who are most likely to spread the flu and have a stronger reaction to the vaccine, would prevent overall mortality.  I have seen many scientists write that our current vaccination strategy is flawed, and that we should focus mainly on the people who might spread it.

Billion Trillion 2

Several people responded to my earlier post by defending the misuse of numbers.  But no matter what you think of the issue, you must agree that this guy is an idiot:

Mr Chiscolm sued Bank of America in Manhattan's federal court in August for "$1,784 billion trillion", in a complaint that boiled down to poor customer service.
...
Judge Chin called the complaint "incomprehensible", in an order released in court.

The fact that he was even allowed to file this complaint is a symptom of how our judicial system is being rotted away by frivolous lawsuits.

Vibram Fivefingers 2

Earlier, I posted my first reactions to my new shoes. 

That pair split a seam, and I sent them back to be replaced under warranty.  It took a couple weeks to get the new pair back.  I started wearing these on Fall Break, and for the past week or so, I have been wearing them around school, except on days when I am in front of the class teaching.

I am still very happy with how they feel, and would recommend them to anyone who likes the feel of walking barefoot.  But if you wear them in public, expect them to attract a lot of attention.  Most people have never seen or heard of shoes with toes.  People who don't know me often stare at them, or at least do a double-take, and people who do know me will often comment on them.

Reactions have ranged from 'So how do you like those FiveFingers?' to 'Toe socks? Really?'  They have been compared to ninja shoes and to frostbitten feet.

I quickly developed a fifteen-second explanation of what they are and why I am wearing them:

"These things were designed for outdoor and water sports.  They fit well and have good traction.  It gives me the health benefits of going barefoot: strengthening the joints and muscles in my legs.  Normal shoes sometimes make my knees ache."

Even strangers have started conversations.  Reenactors at King's Mountain, and sellers at an art show, asked me about them.  This makes sense; these kinds of people are more outgoing and more interested in something new and unique.

I have discovered one weakness in the shoes.  Be warned: Vibram Fivefingers are not good for kicking fire ant nests.  No matter how swiftly I kick them or what angle I strike the mound, there were always a few ants stuck between the toes or clinging to the fabric on the upper part of the foot.

Some people might be bothered by the lack of insulation.  When wearing these, your feet will be colder than normal.  For me, however, this is a big bonus, because my feet normally get too hot, especially when exercising.

China and Africa

An African writer comments on the Chinese presence in Africa:  The long and short if it is that they are ruthless bastards who know how to get a job done:

Here is an example of what I mean: A Korean company was building a highway westwards out of Accra for more than a year.

The work stalled because the authorities could not, or would not, pull down the structures demarcated to be pulled down and for which compensation had been paid.

Indeed, the gossip was that more people started putting up structures after the demarcation exercise so they could be paid compensation - but that is another story.

A Chinese company started building a highway northwards out of Accra.

Once the demarcation was done and the compensation paid, they waited for seven days and one fine Sunday morning, as people made their way to church, they brought out the bulldozers and by the time church was over, the houses and kiosks in their way had all been pulled down.

No amount of shouting or pleading or threatening impressed them - they claimed they couldn't understand English.

After a few days of shock, the communities resigned themselves and concentrated on the beautiful road being built for them.

Meanwhile on the western front, it took for ever before the project could be completed. And guess who got kudos for delivering the work on time?

As I have said before, the Chinese seem to have a comparative advantage in dealing with third world countries.  We should just stand back and let them do the dirty work for us.

Billion Trillion

In class yesterday, while giving a presentation, a student said, "You've all seen those drug commercials where they list like a billion trillion side effects.'

I hate it when people misuse math words like this. People who throw around the biggest math words they know as a synonym for 'many' are cheapening the value of mathematical notation as they reveal their own ignorance.  When I hear this kind of thing, I am reminded of the stereotype of a cave man, whose idea of counting is 'one, two, three, many'.  People who talk like this signal that their brains do not understand how to deal with numbers larger than the number of digits on their hands.

A billion is 10^9.  A trillion is 10^12.  A billion trillion is 10^21.  If you were to actually list a billion trillion items at the rate of one per second, it would take you 3 x 10^13 years, which is several orders of magnitude larger then the age of the entire universe.

Let me put this into more perspective.  Assume that you were only listing a trillion side effects, at the rate of one per second.  It would take you 30,000 years to finish the commercial.  Imagine that an Egyptian doctor invented a medicine in the First Dynasty of the Old Kingdom, with a trillion side effects.  That doctor starts giving a commercial.  He would be listing side effects as all the pyramids were being built, as the Old Testament was being written throughout the entire history of Israel, as all of the Greek city-states rose and fell, and as the Roman empire covered the Mediterranean and then collapsed in upon itself.  He would be listing side effects all during the Dark Ages of Europe, during the centuries of Viking raids, and during the centuries of the Middle Ages.  He would be listing side effects as Columbus sailed the sea, and all throughout the Industrial Revolution and the Enlightenment, continuing through the lives of your grandparents, your parents, and for your entire life until today.

And as of today, he would have finished listing less than one-fifth of the side effects of the medicine.

Hopefully this will reveal the stupidity of throwing around words like 'trillion'.  So don't be like the person in my class.  Use math words properly, and respect their meaning.

Inheritance Laws

Americans have become accustomed to the idea that thay can decide what happens to their money and property when they die.  If they want to give it all to one kid, or to a charity, they can do so.  Choosing how to dispose of one's assets is seen as a natural right.

But our idea of inheritance is actually quite rare.  In most of Europe, there are very strict laws about inheritance.  Most of your estate must be divided evenly between all children.  It is actually illegal to reward good children by giving them more, or to give most of your money to a charity.

It gets worse.  If you give money to a charity while you are alive, your heirs can have the courts force the charity to return the money to them.  This is, to my mind, absolutely insane.  Any law that takes money away from a charity, money that was freely given by the person who earned it, and hands it over to some spoiled rich kid who never did anything to earn it, is mind-bogglingly stupid.  It violates just about every concept of rights and justice that you can think of.

The European laws seem to be the result of a fundamentally flawed concept of human rights.  They believe that all children have the right to their parents' wealth, and that it is wrong for them to be denied it.  This imaginary 'right' results in a direct violation of the rights of the parents and the charities to their property.

The lesson here is that whenever you give people a 'right' to something that was produced by someone else, the result is always this kind of perversity.

One last thought: This might be a factor explaining the low birth rate in Europe.  I know I would be less likely to have kids if I knew that I would be forced to follow these laws.

Technology and Equality

This is a good essay.  It is a bit long, and takes some time to get to the point, so I'll summarize and add a few comments.

There are two types of goods, material goods and positional goods.  Material goods are things like food, clothing, and medical care that directly improve the physical condition of our lives.  These things have gotten much cheaper as technology advances, and will continue to do so in the future.  Positional goods are things like famous artwork, admission to an elite university, or a lake house.  They mainly serve to improve your social status, and technology will not be able to make more of them.

As our material wants and needs are satisfied more and more cheaply, people focus more and more on positional goods.  If you are hungry, your goal in life is to get enough food.  We can, in principle, do this for everybody, making everyone equally well-off.  But material equality never actually makes people happy.  When material needs are met, they typically start chasing positional goods.  But we can't give these to everybody.  The number of positional goods is fixed.  This is inevitable.  If they weren't rare, they wouldn't be status symbols.

So as we get richer and more technologically advanced, society appears more and more unequal as it becomes harder and harder to give everybody what they want.  If the life goal of everyone in the population is to make sure they and their kids have enough to eat and a decent place to live, then everyone can be satisfied.  But if everyone's goal is to send the kid to Harvard, than 99.99% of the population will be disappointed.

So we should expect more and more complaints about income and social inequality, even as technology makes everyone's standard of living go up.

I'll add that material goods are probably less likely to inspire jealousy and zero-sum thinking.  If your neighbor has plenty of food, he hasn't taken anything away from you.  You can work and earn money and get just as much food.  But if your neighbor has a Picasso, then you cannot have it.  Hard work that creates material goods adds value to the world, making everyone better off.  But hard work that chases a positional good doesn't do anyone any good, because nothing has been added to the world.

Thankfully, this is a problem that individuals can easily solve on their own.  Train yourself to stop caring about status symbols and positional goods.  If you know how to be happy with the material comforts that are getting better and cheaper all the time, then the future will be a very enjoyable place for you.  But if you insist on acquiring things that your neighbors do not have, then the future will be an endless rat race for you.