Research Methods · N-of-1 designs · continued

Designing a personal experiment that could change your mind — one year on posts 61–81

Research Methods › N-of-1 designs effect size data table worked example

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

m.ivaturiTL216 Jun 2026#61

Where the Designing 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.

0 likes 1mo

a.silvaTL218 Jun 2026#62

I think the Designing a personal experiment question is answerable and has not been answered, which is a more optimistic position than most of this thread.

31 likes 1mo

o.cousineauTL3Regular20 Jun 2026#63

s.kimani, post #33: Confirming post #30 from a second method, which matters more than confirming it from a second person. Record everything that changed, not just the intervention. Personal experiments are confounded by life, and the confounders are only recoverable if they were written down. Go to post

Everything in post #61 holds. The case it does not cover is the one I have.

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.

Nothing above should be read as advice about what anyone else should do.

11 likes in reply to #33 1mo

s.ferreiraTL222 Jun 2026#64

That is a cleaner way of putting what I was circling around.

3 likes 1mo

s.dziedzicTL224 Jun 2026#65

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.

1 like 1mo

c.adebayoTL226 Jun 2026#66

Building on post #63 rather than restating it.

The most useful thing anyone has posted about Designing a personal experiment in this category was a table of what had been measured and by whom. That is what I would want again.

0 likes 1mo

h.karlsenTL228 Jun 2026#67

Collapsed as off-topic by two members at trust level 3 or above

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.

I would put this at better than even and not much better.

d.barrosTL230 Jun 2026#68

dr_seong, post #28: Post #26 answers the question as asked. The question underneath it is different. 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. Go to post

A note on scope: what I am saying about Designing a personal experiment applies to the case in the first post and I would not extend it further without checking.

6 likes in reply to #28 28d

j.asanteTL22 Jul 2026#69

On post #68 — agreed on the reasoning, with one qualification.

The interesting personal experiments are the ones where the answer was no. They are also the ones least likely to be written up.

3 likes 26d

t.vasquezTL4 Moderator4 Jul 2026#70

Record everything that changed, not just the intervention. Personal experiments are confounded by life, and the confounders are only recoverable if they were written down.

A qualification I should have led with rather than closed on.

0 likes 24d

NardoneTL2Member6 Jul 2026#71

Answering the Designing a personal experiment question as asked, then the question I think is meant. As asked: yes, with the qualification below. As meant: it depends on how the first measurement was taken.

1 like 22d

l.vermeulenTL28 Jul 2026#72

On post #68 — agreed on the reasoning, with one qualification.

Multiple outcomes measured without a primary one means something will move. Nominate the primary in advance and report the rest as secondary.

7 likes 20d

IMainwaringTL3Regular10 Jul 2026#73

Write down what you would accept as evidence that it did not work, before starting. That one sentence turns an anecdote into an experiment.

Anyone with a larger sample, please post it.

24 likes 18d

l.lundgrenTL212 Jul 2026#74

t.abubakar, post #57: 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. Go to post

Quietly grateful for the plain phrasing. Not every thread gets that.

0 likes in reply to #57 16d

TamburelloTL2Member14 Jul 2026#75

Adding the measurement that post #73 says would settle it.

A photograph or a device reading is a harder record than a recollection, and where one is available it should be the record.

Where I would look next, rather than where I would stop.

0 likes 14d

v.okonkwoTL216 Jul 2026#76

Post #72 describes the usual case. This is about the unusual one.

Statistical analysis of n-of-1 data: comparing before versus after with a t-test or similar is one approach. Plotting the data visually is another. Both are valid.

That much is documented. The rest is how I have interpreted it.

4 likes 12d

FFaulknerTL3Regular18 Jul 2026 · edited#77

Reporting the whole series rather than the interesting segment is the discipline that makes personal data worth reading. Selective reporting is the default without effort.

17 likes 10d

h.ramosTL220 Jul 2026#78

d.barros, post #68: A note on scope: what I am saying about Designing a personal experiment applies to the case in the first post and I would not extend it further without checking. Go to post

Taking Designing a personal experiment seriously for a moment rather than deflecting: the honest position is that the community has observations and no controlled comparison, and those two things support very different sentences.

0 likes in reply to #68 8d

CSagredoTL3Regular22 Jul 2026#79

Adding thanks rather than a view. I do not have a view worth the space.

6 likes 6d

r.molnarTL224 Jul 2026#80

Regression to the mean explains a great many personal experiments. People start when things are at their worst, and things at their worst tend to improve.

That is all I can say without guessing.

16 likes 4d

a.silvaTL226 Jul 2026#81

Designing a personal experiment that could actually change your mind: that is the standard for an n-of-1 design. An experiment designed so that any result confirms what you already believed has not changed anything.

I would put the burden of proof on the interesting explanation, not the dull one.

4 likes 2d

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Designing a personal experiment that could change your mind — one year on posts 61–81

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