More Confounders | Slate Star Codex

“So why did they get such different results from so many earlier studies? In their response to Kripke, they offer a clear answer:

They adjusted for three hundred confounders.

This is a totally unreasonable number of confounders to adjust for. I’ve never seen any other study do anything even close. Most other papers in this area have adjusted for ten or twenty confounders. Kripke’s study adjusted for age, sex, ethnicity, marital status, BMI, alcohol use, smoking, and twelve diseases. Adjusting for nineteen things is impressive. It’s the sort of thing you do when you really want to cover your bases. Adjusting for 300 different confounders is totally above and beyond what anyone would normally consider.

Reading between the lines, one of the P&a co-authors was Robert Glynn, a Harvard professor of statistics who helped develop an algorithm that automatically identifies massive numbers of confounders to form a ‘propensity score’, then adjusts for it. The P&a study was one of the first applications of the algorithm on a controversial medical question. It looks like this study was partly intended to test it out. And it got the opposite result from almost every past study in this field.”

—Scott Alexander, “More Confounders.” Slate Star Codex. June 24, 2019.

Open question: Are sleep aids bad for you?

Open question: Are confounders one of the central problems of reproducibility in science?

Found: A Quadrillion Ways for String Theory to Make Our Universe

“According to string theory, all particles and fundamental forces arise from the vibrational states of tiny strings. For mathematical consistency, these strings vibrate in 10-dimensional spacetime. And for consistency with our familiar everyday experience of the universe, with three spatial dimensions and the dimension of time, the additional six dimensions are ‘compacted’ so as to be undetectable.

Different compactifications lead to different solutions. In string theory, a “solution” implies a vacuum of spacetime that is governed by Einstein’s theory of gravity coupled to a quantum field theory. Each solution describes a unique universe, with its own set of particles, fundamental forces and other such defining properties.”

—Anil Ananthaswamy, “Found: A Quadrillion Ways for String Theory to Make Our Universe.” Scientific American. March 28, 2018.

Note to self: read Brian Greene’s Elegant Universe.

Reuters Investigates “The Body Trade”

“Each year, thousands of Americans donate their bodies in the belief they are contributing to science. In fact, many are also unwittingly contributing to commerce, their bodies traded as raw material in a largely unregulated national market.

Body brokers are also known as non-transplant tissue banks. They are distinct from the organ and tissue transplant industry, which the U.S. government closely regulates. Selling hearts, kidneys and tendons for transplant is illegal. But no federal law governs the sale of cadavers or body parts for use in research or education. Few state laws provide any oversight whatsoever, and almost anyone, regardless of expertise, can dissect and sell human body parts.

‘The current state of affairs is a free-for-all,’ said Angela McArthur, who directs the body donation program at the University of Minnesota Medical School and formerly chaired her state’s anatomical donation commission. ‘We are seeing similar problems to what we saw with grave-robbers centuries ago,’ she said, referring to the 19th-century practice of obtaining cadavers in ways that violated the dignity of the dead.”

—Brian Grow and John Shiftman, “The Body Trade.” Reuters. October 24, 2017.

The Cookbooks of Nathan Myhrvold 

“If you are not passionate, a 2640-page cookbook [Amazon cost: ~$500] is not for you…

…I ask Myhrvold for a simple example of how the knowledge of cooking he has developed might help ordinary home cooking.

‘If you have a steak that is twice as thick as the one you cooked the last time,’ he asks me, ‘how much longer is it going to take to cook?’

I say I don’t know exactly. Somewhat longer.

‘Most chefs can’t even tell you exactly,’ he says, ‘because even though it’s a really basic question nobody taught them. The answer is four times. Heating in a steak works by conduction, and conduction has a scaling law that goes by the square of the depth.’

So is there then no intuition or fingertip knowledge to cooking?

‘Sure there is! A Japanese chef cuts fish more quickly and deftly than I can. But if you talk to the guy at the local steak house, he may have an intuitive sense of how long it takes to cook a steak, but it’s from long experience.’

What’s wrong with that?

‘Three things,’ Myhrvold says. ‘First, learning from experience means that you’ve screwed up a lot. That guy has ruined a lot of steaks! Second, learning from experience doesn’t help teaching people. Why not speed things up by telling learners the principles? Third, sometimes the right way of doing something is counterintuitive, as it was with sous vide, and you’ll probably never find it from experience. Active research can uncover new things.'”

—Nathan Myhrvold, “The Physics of Bread.” Physics World. October 2017.

Modernist Cuisine at Home, at just over a $100, might be worth looking into for those folks with the means and lack a public library option.