Posting this under the heading it deserves: Second pass at: Journal club: LEADER as the historical anchor Everything below is what sits behind that.
Two things I would like separated before anyone answers on LEADER, because they get bundled and then argued about as one thing.
The first is descriptive: what has actually been observed, by whom, and how. The second is causal: why. I am asking about the first only.
The version of LEADER that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and those conditions are where the interesting cases live.
The most common failure mode is spending fifty minutes on the effect size and ten on the population. Reversing that ratio would improve most sessions.
If someone has run LEADER properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
Post #6 and I disagree about the size of the effect, not about the direction.
The figures usually contain the finding and the text usually contains the interpretation. Separating them for the first twenty minutes is a discipline worth keeping.
Same conclusion as the reply above, reached differently, which is mildly reassuring.
What I can speak to on LEADER is narrow, so I will keep it narrow rather than generalising from it. Beyond that boundary I do not know.
Reading order that works for these sessions: registry entry, methods, baseline table, primary result, then abstract last. Reading the abstract first anchors everything that follows.
I came in to disagree and I am leaving without a disagreement.
The baseline characteristics table is the single most useful page for the questions that get asked here, because it tells you who the result applies to.
I read post #13 twice before replying, because I had assumed the opposite.
Adding a small correction to the LEADER summary above rather than a disagreement with it. The substance holds; one of the figures is out by a factor that matters.
Post #13 answers the question as asked. The question underneath it is different.
LEADER is a good example of a question where the honest answer is boring and the interesting answers are unsupported. I would go with boring.
Sessions on negative or null results are consistently the most instructive and the hardest to get anyone to attend.
Post #17 describes the usual case. This is about the unusual one.
Where I would push back on the LEADER consensus is the confidence, not the direction. The direction looks right. The confidence is borrowed.
This settles it for me, at least until somebody posts a reason it should not.
This follows post #21 rather than contradicting it.
One more thing on LEADER that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent contradiction disappears.
Worth separating two things that post #20 runs together.
Summarising the LEADER thread so far, since it is long and the answer is buried: the first reply has the method, the fourth has the correction to it, and the rest is people agreeing at length.
I had written a reply contradicting post #24 and deleted it. Here is what survived.
Genuine question rather than a rhetorical one: has anyone here actually observed LEADER, as opposed to read about it? The thread is long and I cannot tell.
The most common failure mode is spending fifty minutes on the effect size and ten on the population. Reversing that ratio would improve most sessions.
Post #26 is the version of this I will quote in future. One addition.
A methods point on LEADER rather than a substantive one: if the comparison is not like for like, the difference you are measuring is the difference in method.
I have no financial interest in anything named in this thread and I want to say so before I comment on LEADER, because it is the sort of subject where it matters.