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Research Methods · N-of-1 designs · continued

Washout with a one-week half-life: the arithmetic posts 61–90

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

JF
j.fonsecaTL23 Dec 2024#61
DO
dr_okonkwoTL4 Moderator4 Dec 2024 · edited#62
trough_index, post #41: 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. Go to post
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Washout periods: after stopping a medication, how long does it take for the effect to wash out? For compounds with a week-long half-life, roughly a month is needed to reach baseline. Using that washout period in a before-after design strengthens the inference.

32 likes in reply to #41 20mo
CG
c.grimaldiTL2 Moderator4 Dec 2024#63

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.

11 likes 20mo
CC
c.cardosoTL2 Moderator4 Dec 2024#64

post #63 is right about the mechanism and I think understates the practical bit.

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.

3 likes 20mo
ML
m.lehtinenTL2 Moderator4 Dec 2024#65
Norrington, post #51: This follows post #48 rather than contradicting it. 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. Go to post

Coming back to post #63, because the follow-up matters more than the original answer.

When to run an n-of-1: this design works when you want to know whether a treatment works for you, not whether it works in general. For that purpose, it is efficient.

0 likes in reply to #51 20mo
NN
n.nybergTL2 Moderator4 Dec 2024#66
ma.nascimento, post #37: 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. Go to post

Picking up post #63: that is the part I would want checked first.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

24 likes in reply to #37 20mo
CL
c.lundgrenTL2 Moderator4 Dec 2024#67

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.

7 likes 20mo
HE
h.eriksenTL2 Moderator5 Dec 2024#68

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.

1 like 20mo
FW
f.weissTL2 Moderator5 Dec 2024#69
r.mwangi, post #7: When to run an n-of-1: this design works when you want to know whether a treatment works for you, not whether it works in general. For that purpose, it is efficient. Go to post

Washout periods: after stopping a medication, how long does it take for the effect to wash out? For compounds with a week-long half-life, roughly a month is needed to reach baseline. Using that washout period in a before-after design strengthens the inference.

3 likes in reply to #7 20mo
CL
customs_ledgerTL35 Dec 2024#70
O
OkaforTL3Regular5 Dec 2024#71

post #70 answers the question as asked. The question underneath it is different.

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.

1 like 20mo
ID
il.dumitruTL2 Moderator5 Dec 2024#72

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.

7 likes 20mo
GH
g.haalandTL3Regular5 Dec 2024 · edited#73

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.

25 likes 20mo
EC
e.coelhoTL2 Moderator6 Dec 2024#74
Norrington, post #51: This follows post #48 rather than contradicting it. 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. Go to post

Coming back to post #72, because the follow-up matters more than the original answer.

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

0 likes in reply to #51 20mo
M
MJayawardenaTL3Regular6 Dec 2024#75

post #74 is right about the mechanism and I think understates the practical bit.

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.

4 likes 20mo
DN
d.nilsenTL2 Moderator6 Dec 2024#76

Worth separating two things that post #72 runs together.

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.

12 likes 20mo
O
OTeixeiraTL3Regular6 Dec 2024#77

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

0 likes 20mo
FI
f.ibarraTL2 Moderator6 Dec 2024#78
LJankowiak, post #45: On post #41 — agreed on the reasoning, with one qualification. Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing. The correction was fair and I had been repeating something I had not checked carefully enough. Go to post

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.

0 likes in reply to #45 20mo
GI
g.ibarraTL2 Moderator6 Dec 2024#79
r.frisk, post #18: Worth separating two things that post #14 runs together. When to run an n-of-1: this design works when you want to know whether a treatment works for you, not whether it works in general. For that purpose, it is efficient. Go to post

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.

0 likes in reply to #18 20mo
SC
s.cardosoTL2 Moderator7 Dec 2024#80

On post #76 — agreed on the reasoning, with one qualification.

Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own records is not any individual result; it is that they are dated and consecutive.

2 likes 20mo
RM
r.marsdenTL3Regular7 Dec 2024#81
il.dumitru, post #72: 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. Go to post

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.

0 likes in reply to #72 20mo
FF
f.fontaineTL2 Moderator7 Dec 2024#82
taper_file, post #55: Picking up post #52: that is the part I would want checked first. 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. Go to post

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

31 likes in reply to #55 20mo
L
LeitermanTL3Regular7 Dec 2024#83

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.

16 likes 20mo
NS
n.serranoTL2 Moderator7 Dec 2024#84

Picking up post #81: 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.

6 likes 20mo
B
BBramleyTL3Regular7 Dec 2024#85
c.lundgren, post #67: 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. Go to post

Worth separating two things that post #81 runs together.

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

0 likes in reply to #67 20mo
GE
g.ekstromTL2 Moderator8 Dec 2024 · edited#86
integrator_trace, post #49: 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. Go to post

Washout periods: after stopping a medication, how long does it take for the effect to wash out? For compounds with a week-long half-life, roughly a month is needed to reach baseline. Using that washout period in a before-after design strengthens the inference.

23 likes in reply to #49 20mo
JH
j.habermannTL3Regular8 Dec 2024#87

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.

11 likes 20mo
KO
k.okaforTL2 Moderator8 Dec 2024#88

Blinding: blinding yourself (not knowing which condition you are in) removes expectation bias. This is hard to do with these compounds (the appetite suppression is hard to miss) but partial blinding is possible (measuring something objective without knowing whether you took it today).

3 likes 20mo
RH
revision_historyTL3Wiki editor8 Dec 2024#89

On post #85 — agreed on the reasoning, with one qualification.

When to run an n-of-1: this design works when you want to know whether a treatment works for you, not whether it works in general. For that purpose, it is efficient.

3 likes 20mo
EM
e.mbekiTL2 Moderator8 Dec 2024#90
g.ibarra, post #79: 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. Go to post

post #89 answers the question as asked. The question underneath it is different.

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.

0 likes in reply to #79 20mo