Comments on: Health Hopes Spring Eternal

By: A broader view

A broader view — Wed, 17 Oct 2007 02:59:21 +0000

Does Diet AffectCholesterol?

The usually insightful Overcoming Bias had a post about the Framingham study, a logitudinal survey which found no correlation between diet and cholesterol. Robin quotes an article from the Framingham newspaper; his take is that Kannel is trying to be c…

By: nick

nick — Tue, 16 Oct 2007 04:00:05 +0000

Robin, my observations were based on no experimental data that I know of, just my own personal experience and some combination of reasoning and gut instinct. Anyway, if somebody wishes to test my theory here is a more precise statement: normalizing for IQ and education, an Asperger’s person will have a more accurate opinion of a physical fact (such as the energy savings from turning a light off inside when it’s cold outside and one is trying to heat the house) than a a non-Asperger’s person, where opinion of that fact can be biased by social signalling considerations (such as the benefit from being seen as a person who conserves energy). There may be other syndromes besides Asperger’s involving a deficit of social signalling that might also work here.

By: g

Mon, 15 Oct 2007 00:25:10 +0000

Since different people will be capable of different levels of compliance, it would be good to decouple compliance from efficacy-given-compliance. If some dietary change is beneficial when actually followed but (for whatever reason) not usually followed by participants in studies, someone with above-average motivation or different tastes might be able to get more benefit from the change than non-decoupled studies would suggest. If they knew about it, which they never would if non-decoupled studies were the only ones.

(Note that decoupling compliance from efficacy-given-compliance doesn’t have to mean just excluding non-compliant subjects. You could, obviously, publish the numbers both ways.)

This all seems very obvious, but it also seems to make it silly to be dismissive about someone who says he thinks a good study should enable this sort of decoupling, so maybe it’s less obvious than it seems.)

By: Douglas Knight

Douglas Knight — Sun, 14 Oct 2007 22:43:17 +0000

3. measured compliance so that non-compliant subjects were excluded.

translation: you’re not willing to bet.

Compliance is a big deal and it cuts both ways: it means that the effect measured in the study is less than the potential effect, but it also means that the effect measured in the study is greater than the effect will be in practice. I suspect this (and other ways that studies aren’t representative) is an important part of the discrepancy between studies and practice.

By: Seth Roberts

Seth Roberts — Sun, 14 Oct 2007 16:29:07 +0000

I’d bet on a clinical trial about omega-3 and gum disease that

1. used flaxseed oil.

2. got the dose right (at least 1 Tbsp/50 pounds body weight)

3. measured compliance so that non-compliant subjects were excluded.

By: Seth Roberts

Seth Roberts — Sun, 14 Oct 2007 06:05:37 +0000

Robin,

My belief that in case of omega-3 and gum disease, the clinical trials — which failed to make the connection — were wrong and Tyler’s experience — which showed a strong connection — was right is supported by lots of facts: 1. Thousands or more cases where supplying a missing nutrient quickly cured a problem. E.g., lime juice and scurvy. 2. Evidence that gum disease is due to inflammation. 3. Evidence that omega-3 reduces inflammation. 4. My self-experimental results that show that flaxseed oil in certain doses (which Tyler used) had whopping effects on brain function. 5. The effects of flaxseed oil on my gums.

By: Doug S.

Doug S. — Sun, 14 Oct 2007 04:01:18 +0000

Seth, just because a person gets better after seeing a quack doesn’t mean that the quack cured them.

By: Robin Hanson

Robin Hanson — Sun, 14 Oct 2007 00:07:38 +0000

Nick, is there any data to support your hypothesis?

By: Richard Hollerith

Richard Hollerith — Sat, 13 Oct 2007 22:33:41 +0000

What nick said.

By: Mike Kenny

Mike Kenny — Sat, 13 Oct 2007 18:34:55 +0000

I was pondering this regarding self experimentation: how often is it likely a personal experience would reflect an average experience among people? If I pinch myself and see that as a result I feel pain, and assume others would report the same cause and effect relationship, I’d be right, but if I read Thomas Pynchon and liked it, and assumed everyone else did, I’d be wrong.

This connects with what I said in the October Open Thread section. It’d be useful to know how often certain things seem to be true, in more than just an intuitive way. I have an intuitive sense of how often people are right when they tell me something, but I don’t have an actual record. It’d be great to have a table based on sampling that suggests the probability of certain common experiences being true. One useful probability figure to know would be the answer to the question “How often is my personal experience generalizable?” It may be very low (though would it? Wouldn’t the likelihood of your experience being average be the most reasonable assumption?), but even a low probability might be useful if the potential benefits are great of generalizing based on personal experience, and the costs are very likely low.