Journal club: STEP 1 and the treatment-policy estimand — does this still hold?

Everything in post #4 holds. The case it does not cover is the one I have.

Since STEP 1 keeps coming up, it should probably be a maintained page rather than a recurring thread. I am happy to draft it if someone with more direct experience will review it.

Answering the question post #11 raises rather than the one it answers.

Second-hand on STEP 1, so weight it accordingly — someone whose method I trust told me this and I have not verified it myself.

The question underneath STEP 1 is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it.

Write down what you would expect to see under each hypothesis before you collect anything. If they predict the same observation, collecting it will not help.

I had written a reply contradicting post #40 and deleted it. Here is what survived.

Sessions on negative or null results are consistently the most instructive and the hardest to get anyone to attend.

I would rather say I do not know than round it up to an answer.

Post #46 answers the question as asked. The question underneath it is different.

Adding the boring version of STEP 1, because the interesting version keeps getting posted and the boring one is usually right.

Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.

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.

Caveat: everything above assumes the paperwork is what it says it is.

STEP 1 is a question about a distribution, not about a value, and treating it as a value is what produces the confident wrong answers.

Where the group cannot agree, record the disagreement rather than resolving it by seniority. The recorded disagreement is more honest and more useful later.

Speaking for myself and not for anyone else who has posted here.

STEP 1 is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says which one is being asked for.