Pre-registering a personal experiment, seriously — a second dataset posts 31–60
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Where the Pre-registering a personal experiment reasoning breaks down for me is the step from the group result to the individual case. That step is almost never argued for.
Duration should be set by how long an effect would take to appear rather than by patience. Stopping early is the commonest reason a personal experiment answers nothing.
If anyone has run this properly I would rather read that than my own guess.
Nothing in a personal experiment is medical advice to anyone including yourself, and several people here have found that a prescriber will happily discuss a well-documented one.
Not a conclusion. A place to stand while looking for one.
On Pre-registering a personal experiment, the part that usually goes wrong is that the question is asked as though it has one answer. It has a range, and the width of the range is the interesting bit.
If you can post the two or three numbers you are working from, several people here will check the arithmetic rather than argue about the conclusion.
Narrowing post #35, because the general version has more than one answer.
Pre-registering a personal experiment has been discussed here with more heat than it deserves, mostly because two definitions have been in play the whole time.
Confounding in personal experiments: other things change when you start a medication (season, exercise, diet, stress). Documenting those confounders helps you understand their contribution to the result.
A single-person experiment can be genuinely informative if it has a pre-specified outcome, a defined period, and a plan written before the data arrives. Most accounts here have none of those.
It took me longer than it should have to see that.
Answering the question post #38 raises rather than the one it answers.
Pre-registering a personal experiment sits at the boundary between what this community can usefully discuss and what it cannot, and I think it falls on the discussable side, narrowly.
I would call the community position on Pre-registering a personal experiment likely rather than established, and I would be comfortable defending that hedge.
Adding the measurement that post #43 says would settle it.
Write down what you would accept as evidence that it did not work, before starting. That one sentence turns an anecdote into an experiment.
Two people can read the same figure differently here and both be reasonable.
Post #42 describes the usual case. This is about the unusual one.
Blinding yourself is harder than it sounds and is not impossible. Somebody else preparing labelled containers is the usual approach and it requires a second person you trust.
Noting that the question and the thing people usually mean by it are different.
I will take the caveat as seriously as the claim, which is the point of putting it there.
Write down what you would accept as evidence that it did not work, before starting. That one sentence turns an anecdote into an experiment.
On post #50 — agreed on the reasoning, with one qualification.
Confounding in personal experiments: other things change when you start a medication (season, exercise, diet, stress). Documenting those confounders helps you understand their contribution to the result.
A partial answer, offered because a partial answer beats none.
Blinding yourself is harder than it sounds and is not impossible. Somebody else preparing labelled containers is the usual approach and it requires a second person you trust.
Reading it back, the second half matters more than the first.
Post #53 is right about the mechanism and I think understates the practical bit.
Generalisability: a robust n-of-1 result applies to you. It does not tell you much about whether the effect generalises to others similar to you, much less to people different from you.
This is the sort of thing the wiki should carry and currently does not.
Nothing to add on the substance. Thank you for taking the question at face value.
I had written a reply contradicting post #53 and deleted it. Here is what survived.
Order effects matter. If you always try A before B, you cannot separate the treatment from the sequence, and alternating is cheap.
The short version is the first sentence; the rest is why.
Collapsed as off-topic by two members at trust level 3 or above
Confirming post #57 from a second method, which matters more than confirming it from a second person.
Pre-registering a personal experiment has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.
Taking post #57 at face value and following it one step further.
An n of one tells you about one person, which is the person you are most interested in. That is the whole value and it is not nothing.
Adding this to the thread rather than to the wiki, because I am not confident enough for the wiki.