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Topic summary

Comparators chosen for regulatory reasons rather than clinical ones — one year on

This is a generated summary. It shows the 9 most-liked posts from a topic of 88, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.
SG
s.grahameTL2Member22 Mar 2025#1

Comparators chosen for regulatory reasons rather than clinical ones — one year on — setting out what I have, and where I think it stops being reliable.

Posting a small dataset on Comparators chosen for regulatory reasons. It is mine, it is uncontrolled, and the method is stated so it can be discounted appropriately.

What I would like is not agreement but a second dataset collected by someone with no stake in mine. If one exists I would rather read it than argue for this one.

39 likes 16mo
YR
y.rahimiTL22 Apr 2025#5

Pre-specification is the property that makes a primary endpoint trustworthy. An endpoint chosen after seeing the data can be the best endpoint in the world and it no longer carries the same guarantee.

A single observation, in a thread that deserves better than single observations.

28 likes 16mo
MA
m.adeyemiTL2 Solution10 Apr 2025#9

Absolute and relative effects answer different questions. Write down the event rate in each arm and the difference between them; everything quotable is derived from those two numbers.

That is one dataset and I would not build a rule on it.

10 likes 16mo
K
KLindqvistTL4 Moderator3 May 2025#22

A note on scope: what I am saying about Comparators chosen for regulatory reasons applies to the case in the first post and I would not extend it further without checking.

32 likes 15mo
IT
integrator_traceTL2Member22 May 2025#35
a.ibarra, post #23: Everything in post #19 holds. The case it does not cover is the one I have. Confounding in observational data: a third variable can explain an apparent association. In a randomised trial, randomisation balances unknown confounders. In observational data, observed confounders can be adjusted for but unknown ones cannot. Go to post

This follows post #34 rather than contradicting it.

Comparators chosen for regulatory reasons is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly. Worth twenty minutes before adding to this one.

30 likes in reply to #23 14mo
AL
aliquot_lineTL3Regular30 May 2025#41
e.ferrari, post #28: Adding a note of thanks rather than an opinion. I did not know most of that. Go to post

Where the Comparators chosen for regulatory reasons discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are the same sentence with different clothes on.

32 likes in reply to #28 14mo
JL
j.lokkenTL211 Jun 2025#50
h.fonseca, post #34: I had written a reply contradicting post #32 and deleted it. Here is what survived. Absolute and relative effects answer different questions. Write down the event rate in each arm and the difference between them; everything quotable is derived from those two numbers. Go to post

Building on post #49 rather than restating it.

Multiplicity and multiple comparisons: if a trial tests many hypotheses, the chance of a false positive on at least one by random chance increases. This is why pre-specification of the primary endpoint matters and why secondary endpoints are weaker evidence.

30 likes in reply to #34 14mo
BD
b.dumitruTL225 Jun 2025#61
a.weiss, post #27: I read post #23 twice before replying, because I had assumed the opposite. What I would tell a new member reading about Comparators chosen for regulatory reasons for the first time: the confident posts are not the reliable ones, and the reliable ones are longer. Go to post

Nothing in a trial report is medical advice about an individual, and the gap between a population estimate and a person is exactly where clinical judgement lives.

If anyone has run this properly I would rather read that than my own guess.

27 likes in reply to #27 13mo
SO
s.okaforTL212 Jul 2025#75

This follows post #74 rather than contradicting it.

Risk of bias: structured appraisal of internal validity. Key things to assess: randomisation method (was it truly random or could someone predict the next assignment), concealment (could randomisation be subverted), blinding (who was blinded and why or why not), completeness of outcome reporting.

Reading it again, the caveat matters more than the finding.

28 likes 13mo

Read the full topic (88 posts)

Promoted into the documentation commons. The content of this topic is maintained at STEP 2 — trial digest, with named maintainers and a review date. The promotion was discussed in doc review. Corrections are best raised against the document, which is the version that gets kept current.

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