Month: October 2008

Jane Jacobs on Experts

Seth Roberts1 Comment

Her leitmotif was a swipe at the whole notion of expertise. She went to work for Architectural Forum, she told me, when the Office for War Information was consolidating its staff in Washington, and she didn’t want to leave New York. . . .

“I went to Architectural Forum, and they said well, you’re now our school and hospital expert,” she explained. “That was the first time I got suspicious of experts. I knew nothing, not even how to read plans.” She paused for a moment. “Anybody who would want to be an expert, I have some advice for you: apply at a magazine.”

From an article by Paul Goldberger.

Dutch Unmentionables

Seth Roberts3 Comments

My friend in Holland wrote again:

Dutch people might say that they think the Queen should be democratically elected, but they never say, “She owns Royal Dutch Shell, if she paid taxes on the $4 billion contract she just signed with the Pentagon last week, I wouldn’t be paying 42% on my income… We need to re-examine that.” They’ll talk about the golden horse-drawn carriage she rides around in on Prinsjesdaag, and how cool it looks on TV. And what an impartial symbol of Dutchness she is.

Is Your Milk Safe? A Statistical Fable

Seth Roberts1 Comment

This recently happened in a class at the Beijing Language and Culture University:

TEACHER Your milk is safe if you buy it at a supermarket.

STUDENT What do you mean, “supermarket”? Where else could you buy it?

TEACHER That’s a good question, I don’t know the answer. They told us to say that.

When analyzing their data, a vast number of scientists more or less blindly do what a statistics book told them to do, just as this teacher said what she’d been told to say. Even worse, a vast number of statistics textbook writers simply copy other textbooks (not word for word, just the ideas and recommendations). The scientists and the textbook writers take refuge in false certainty. They fail to grasp that although the recommendations are black and white, the world is not — just as it isn’t black and white what milk is safe. Unlike this particular classroom, no one questions this.

Thanks to Sally McGregor.

Learning Chinese in Beijing

Seth Roberts4 Comments

Learning Chinese here — at least the first baby steps — has turned out be easier than expected. I’d expected to hire tutors. A Berkeley grad student I know who had lived near where I live now had done that. I found ads offering tutoring on a craigslist-like site. I started with the cheapest ($10/hour — which is a lot in Beijing). After an hour, I cut short the first lesson. It had been excruciating. “X means this. Y means that.” In my tutor’s defense, we didn’t yet have a textbook to work from but paying $10/hour for a textbook reader seemed pricey. By then, two people — a Tsinghua student I’d met in a dining hall and the girl who sold me my cell phone — had offered me free Chinese lessons.

“Why should I pay you if others will teach me for free?” I asked my tutor.

“Why did I spend four years in college learning how to teach Chinese to foreigners?” she replied. (That was her major.)

That wasn’t persuasive, I said.

She said she had a Mandarin accent but others might not.

“To speak with everyone I should learn from everyone,” I said. This is an attractive feature of Beijing: It’s much more a melting pot than other Chinese cities, such as Shanghai.

By now I’ve had several lessons from three different people who offered to teach me for free. It felt like fun, not work. They volunteered to teach me because they would learn English at the same time. Most Tsinghua students want to go graduate school in America, where they can expect to do very well — Dark Matter notwithstanding — so long as their English is adequate. I may be at the exact place on earth — the Tsinghua campus — where English-speaking ability is valued most highly. It might be a special time, too: As the Chinese educational system improves its teaching of English, I expect the value will go down. If I were in Sweden, no one would volunteer to teach me Swedish.

The difference between my paid and unpaid teachers reminds me of a famous psychology experiment on extrinsic versus intrinsic motivation done by Mark Lepper and colleagues at Stanford and published in 1973. They took two groups of kids and put them in a room full of toys. One group was told they would be rewarded if they played with the toys. The other group wasn’t told this. Two weeks later, the kids were put back with the toys. Kids rewarded for playing with the toys played less with them than the other kids did. It’s such a profound effect it’s like there are two different motivational systems.

What Should Double-Blind Placebo-Controlled Trials Be Replaced With?

Seth Roberts3 Comments

For a sick person, which is worse?

1. Getting better for the wrong reason.

2. Wasting a lot of money.

It sounds like a joke — #1 isn’t even harmful, whereas the cost of health care is a very serious problem. Yet the FDA and legislators with FDA oversight have been given this choice — and chosen #1. They have chosen to protect us against #1 but not #2.

If you get better from a placebo effect, that’s the wrong reason. How dare you! The requirement that drugs be better than placebo controls prevents this from happening. The requirement might have been — but isn’t — that a new drug be better than pre-existing alternatives. Many aren’t but they are always more expensive — not to mention more risky.

How to Spot Incompetence

Seth Roberts10 Comments

Nassim Taleb says, “When someone says he’s busy, he means that he’s incompetent.” I think he also distrusts anyone wearing a tie. In college, I wrote an essay called “The Scientific _______” in which I argued that any writer who uses the term scientific without explaining what it means is incompetent and you should stop reading immediately.

I still believe that. Now, for the first time, I am going to update my list of incompetence giveaways: Plotting something on a raw scale that should be on a log scale. Size-versus-time data should usually have the size axis on a log scale.

This presentation by someone at Sequoia Capital, the Silicon Valley venture capital firm, is full of examples. The Dow Jones Industrial Average (from the 1960s to now) is on a raw scale (where the distance from 5 to 10 equals the distance from 10 to 15), should be on a log scale (where the distance from 5 to 10 equals the distance from 10 to 20). Same for an index of housing prices. Same for the Nikkei. Many other examples. You can still believe the data, of course; just don’t trust what’s concluded from the data. Given the ubiquity of this practice (plotting on a raw scale what should be on a log scale), especially among financial supposed-experts, Taleb and I are not far apart.

More Taleb makes a similar point in his online notebook. Writing about a debate with Charles Murray:

Finally I showed a graph of the rise of the US stock market since 1900, on a regular (non-log) plot. Without logarithmic scaling we see a huge move in the period after1982 —the bulk of the variation comes from that segment, which dwarfs the previous rises. It resembles Murray’s graph about the timeline of the quantitative contributions of civilization, which exhibits a marked jump in 1500. Geometric (i.e. multiplicative) growth overestimates the contribution of the ending portion of a graph.