This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.
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.
I am not the right person to answer the follow-up to this.
It does not tell you about anybody else, which is why aggregating these accounts does not produce evidence of the kind people want it to.
The mechanism is plausible, which is not the same as established.
Confirming post #31 from a second method, which matters more than confirming it from a second person.
Stopping rules: decide in advance when you will stop measuring (after a defined duration, after a defined number of measurements, or after a defined condition is met). Not deciding in advance means stopping when the result satisfies you, which is bias.
Post #32 describes the usual case. This is about the unusual one.
Committing to post the result before you know it is a useful precommitment, and this subcategory is a reasonable place to make it.
A photograph or a device reading is a harder record than a recollection, and where one is available it should be the record.
The answer changed when I changed how I was measuring, which was informative.
Answering the question post #36 raises rather than the one it answers.
Sample size in n-of-1: you are the sample. Repeated measurements (weekly weighings, daily mood scores) increase the power to detect a real effect even though n=1.
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.
I am reporting what happened, not recommending it.
Seconded. It reads as careful rather than confident, which is the right register.
Everything in post #41 holds. The case it does not cover is the one I have.
Order effects matter. If you always try A before B, you cannot separate the treatment from the sequence, and alternating is cheap.
Narrowing post #41, because the general version has more than one answer.
A rolling mean over several days is far more informative than any single reading for anything that varies day to day, which is nearly everything.
Speaking for myself and not for anyone else who has posted here.
A photograph or a device reading is a harder record than a recollection, and where one is available it should be the record.
Taking post #45 at face value and following it one step further.
Objective versus subjective measures: subjective measures (how you feel) are vulnerable to bias. Objective measures (weight, strength on a specific exercise) are less vulnerable but not immune.
I read post #45 twice before replying, because I had assumed the opposite.
The interesting personal experiments are the ones where the answer was no. They are also the ones least likely to be written up.
I would rather be precise about what I do not know than vague about what I do.
Multiple outcomes measured without a primary one means something will move. Nominate the primary in advance and report the rest as secondary.
The literature is thinner on this than the confidence in the thread implies.
I had written a reply contradicting post #45 and deleted it. Here is what survived.
Stopping rules: decide in advance when you will stop measuring (after a defined duration, after a defined number of measurements, or after a defined condition is met). Not deciding in advance means stopping when the result satisfies you, which is bias.
It does not tell you about anybody else, which is why aggregating these accounts does not produce evidence of the kind people want it to.
That is the shape of it. The detail is where I would expect to be corrected.
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.
If this contradicts something upthread, the upthread version may well be the better one.
Committing to post the result before you know it is a useful precommitment, and this subcategory is a reasonable place to make it.
That is a description of practice, not a recommendation of it.
Picking up post #52: that is the part I would want checked first.
Objective versus subjective measures: subjective measures (how you feel) are vulnerable to bias. Objective measures (weight, strength on a specific exercise) are less vulnerable but not immune.
A photograph or a device reading is a harder record than a recollection, and where one is available it should be the record.
Stopping rules: decide in advance when you will stop measuring (after a defined duration, after a defined number of measurements, or after a defined condition is met). Not deciding in advance means stopping when the result satisfies you, which is bias.
Genuinely open to being wrong about this one.
Order effects matter. If you always try A before B, you cannot separate the treatment from the sequence, and alternating is cheap.
Two people can read the same figure differently here and both be reasonable.